panic attack followed by headache that doesn't want to go away

[Limoges Diver]

I had two incidents last week (it's Sunday morning of labour Day Weekend as I'm writing this):
On Tuesday, I went on a charter dive on the St. Lawrence River in Brockville,Ontario. There was a strong current, but nothing insurmountable. The boat was tied off at a buoy, and there was a 2" diameter rope running from the aft of he boat to the bow, and eventually to the buoy. I was the first to enter the water: I jumped in, wing partly inflated floated up to the surface - everything OK so I motion to the Captain my OK, and I swim the the bow of the boat to grab a hold of the rope. As I'm waiting for the rest of our group, I find myself struggling to breath properly. I get the feeling of Co2 retention, so I close my eyes and try to lax and take deep breaths, and exhale completely. It doesn't work, and I start to get a headache, and I decided then to cancel my dive. I swam to the back of the boat (still feeling panicky, but less as I get back in the boat). After I got on, I had wobbly legs, feeling of dizziness, weakness, and a headache. I attributed this to low blood sugar levels as I had not eaten anything for almost 5 hours prior. I had drank fluids before the dive, so I don't think it was dehydration. After the I got back on chore, I took some pain killers and ate dinner, and the next morning I felt good, although a bit tired.
On Friday, I decided to do a shore dive on a lake (i.e. no current). I knew the waters pretty well, and I made sure I was well-fed, well-hydrated, and that my gear was working well(checked regulator pressure (low pressure was 140 psig as per the manufacturer's instructions). I inflate my wing, and use my snorkel as I'm swimming on the surface to deeper waters. I'm making sure I am not exerting myself physically, and that my breathing is normal. When I get to waters that are about 5-6 feet deep I decide to go underwater. So I switch to my regulator, and breath for a while on the surface with it to get accustomed to it. After I feel I am breathing OK, I deflate my wing, and descend to the bottom.
I swim down slowly to 10-11 feet, and was using my fins a bit, but not much - I was just swimming slowly, observing fish, etc... All of a sudden I get that feeling of Co2 retention, and get that shortness of breath. So instead of bolting up to the surface, I do as I was instructed to do, and stop, relax, close y eyes, concentrate on taking deep breaths, and on exhaling them completely so I don't get Co2 retention. Well, that didn't last very long. After about 10 minutes underwater, I surfaced. Since I had only been 10 feet down, and only for a short time, I didn't think I needed to do anything other than surface and inflate my wing, and swim to shore. Now I don't know how long I took to surface, but suppose I didn't do it in 10 seconds (following the 1 second per foot rule), but most likely in 5 seconds...
I then surfaced, and had a panic attack. I knew I wanted t rip off all my gear and swim ashore (I was about 100 feet from being able to touch the bottom with my feet), but I kept my head on my shoulders, and started to swim to shore with my gear on. I was very low on energy at that point, so I called out to a guy on shore and asked for help. he swam out to me, and helped me back to shore. By the time I got on sore, I had a pounding headache and my neck muscles on he back of my neck hurt real bad. I felt almost nauseous , very week (BTW, I had not over-exerted myself - I run, hike, etc... a lot more than what energy I expended then - I was doing very relaxed dive), but the main thing was this splitting head ache that hurt with every beat of my heart.
That headache and neck pain started at 4:30 ish when I had the panic attack, and got a bit better once I got back to camp. All day Saturday I still had the headache and neck pain (ibuprofen is helping a bit, but not much). If I was to chart t pain levels with 10/10 being 4:30 Friday, by Saturday morning it was about 7.5/10, and this morning 9:00 AM Sunday it's about a 5.5/10

Any ideas why I have this headache and neck pain? As it's the long weekend, i won't be able to see a specialist for a couple days, and I don't trust the emergency room doctors (that got stuck with the Labour Day Weekend ****) at the local hospital (I'm back at home in the middle of farmland) to know anything about diving accidents.

My main confusion centres around the fact that I was only at 10 feet and only 10 minutes underwater and not under physical exertion. Also, I knew my regulator was OK since I had used it on multiple dives a couple weeks prior, and checked the delivery pressure - I also made sure the valve was open all the was by taking deep breaths ad checking for the pressure gauge to make sure it didn't go down (indicating a problem with the regulator or a partially-open valve).

Thanks.

[dmoore19]

Did you use the same tank on both dives? Have you checked the gas in the tank?

[Limoges Diver]

Did you use the same tank on both dives? Have you checked the gas in the tank?

No, I used two different tanks filled at two different places. The last tank (which I own - not rent like the one on Tuesday) was filled at my LDS, which I have 100% confidence in. So, since it was two different places and two different tanks, I think that the air quality is not an issue. Also, the air didn't smell bad, as I check it every time. Now my tank is still full of air (about 2800 psi), so I can get it tested.

[DevonDiver]

Demanding dive = elevated stress = faster, shallower breathing = CO2 retention = persistent headache.

That's my guess, regardless of attempted breath control. Panic attack upon surfacing tends to substantiate this.

A demanding dive is anything that can potentially take you beyond your comfort zone, physically or mentally.

Lesson to be learnt: Know when to abort/abandon a dive. Regardless of experience levels, I wouldn't have gotten into the water if I was in the state you describe.

[Limoges Diver]

Demanding dive = elevated stress = faster, shallower breathing = CO2 retention = persistent headache.

That's my guess, regardless of attempted breath control. Panic attack upon surfacing tends to substantiate this.

A demanding dive is anything that can potentially take you beyond your comfort zone, physically or mentally.

Lesson to be learnt: Know when to abort/abandon a dive. Regardless of experience levels, I wouldn't have gotten into the water if I was in the state you describe.

I wasn't in that state before the dive: I was relaxed (even had a nap that afternoon), well-fed, hydrated,and was really enjoying myself.The dive wasn't demanding - I was only at 10 feet in no current, and all my gear felt good, etc... I was in my comfort zone.
I don't know about elevated stress, but the attempted and aborted dive on Tuesday was on the back of my mind, but I was not thinking about it once I was underwater: I felt great, was relaxed, and was able to reason clearly. It just came out of nowhere. I will get my regulator checked out though - gotta make sure I have enough air.

[TSandM]

You said you checked the intermediate pressure on your regulator -- but did you check the cracking pressure? Does your reg have a pre-dive setting, and if so, are you sure it was not still set on that? This really, really sounds like CO2 to me, and having the cracking pressure too high can set you up for that.

Failing that, if this was the SAME tank, is it possible you got a bad fill which, even when topped off at your LDS, had enough of something in it to give you symptoms?

[melanie.]

Have you ever experienced migraines?

The weakness, dizziness, lack of energy, neck pain, feeling your heartbeat in your head are all symptoms I get. The majority of times my head will hurt but not always.

Perhaps you are pinching a nerve, tilting your head weird, or straining something you are unaware of that is causing a migraine? Making your body feel "not-right" and having the need to get the heck out of the water.

Just another angle to consider. It doesn't explain everything but maybe something to rule out

[Limoges Diver]

You said you checked the intermediate pressure on your regulator -- but did you check the cracking pressure? Does your reg have a pre-dive setting, and if so, are you sure it was not still set on that? This really, really sounds like CO2 to me, and having the cracking pressure too high can set you up for that.

Failing that, if this was the SAME tank, is it possible you got a bad fill which, even when topped off at your LDS, had enough of something in it to give you symptoms?

No, it was not the same tank at all.

What is this cracking pressure you are referring to? Pardon my noobiness.

Also, why would a headache last over 48 hours? I still have it, although it is reduced considerably. It just boggles my mind how 10 minutes under water can result in this.

[Limoges Diver]

Have you ever experienced migraines?

The weakness, dizziness, lack of energy, neck pain, feeling your heartbeat in your head are all symptoms I get. The majority of times my head will hurt but not always.

Perhaps you are pinching a nerve, tilting your head weird, or straining something you are unaware of that is causing a migraine? Making your body feel "not-right" and having the need to get the heck out of the water.

Just another angle to consider. It doesn't explain everything but maybe something to rule out

Thanks for the idea: No, I have not had migraines ever and I'm 48 years old.

Re pinched nerve - my wife thinks it could be that, but I don't know how I could get the Co2 retention symptoms like that. I'm more inclined to believe it's a problem with my regulator not delivering the right amount of air when I need lots of it. I will get my regs checked out and see what the technician says.

[TSandM]

Cracking pressure is how much suction you have to put on the regulator to get the valve to open and deliver air. It should be almost, but not quite effortless. When regulators have a "pre-dive" setting, what that does is increase the cracking pressure, to make it more difficult for air to come out and reduce the likelihood of freeflows. If you don't change that to "dive", you have to work harder than you should to draw air from the regulator, and this can increase the chance of CO2 retention.