Recurring issue - nausea, headaches & throwing up during dives

Hi there. I'm brand new to this forum, and I'm hoping that someone may have some insight to an issue I've been having throughout my diving experiences. I apologize that it's a long message, but it's quite scary.
I've done around 35 dives in total, and have thrown up on about 6 of them. This has happened in different countries over different years, so it's not the air. And I haven't felt sick while on the boat for any of them either, but only while in to the dive.
I tend to feel a bit nauseous, then get a terrible headache which is quickly followed by tunnel vision and a difficult time concentrating (I think because of how much pain I'm in). I believe this is similar to a migraine. The headache becomes excrutiatingly painful, and then I throw up. Some times just a couple of times and sometimes quite violently. The pain doesn't subside once I've thrown up, but I can usually concentrate a bit better. I don't panic when it's happening (okay, I guess I did the first time it happened), but just accept that it will be fine. However, the last time it happened, we were on a drift dive, and couldn't surface. So I continued the dive, throwing up the entire time ... yes, at least 20 times! The pain was unbearable in my head, and the vomitting continued on the boat and on the shore. I honestly thought my skull was going to crack open. I drugged myself to sleep and woke up feeling much better. I made sure to go on another dive 2 days later to "jump back on that horse" sort of thing. I love diving! (when it goes the way it should)
Has anyone else shared this experience or witnessed it or heard of something similar? I'd love to hear some advice. I've been to see a specialist, but apparently my ears are fine. I believe that it could be while I'm on drift dives that this is happening ... needless to say, I'm not planning on doing any more of those just in case.
Thank you very much.

So sorry to hear of your difficulty. I've actually vomited mid-dive myself and there are a variety of issues which can be quite problematic. What's your sinus Hx.?

Well, all the symptoms you describe COULD be due to CO2 retention. Are you diving your own gear, or using rental regs? Did the regs seem hard to breathe at all? Were you working against the current at all, or was your gas consumption unusually LOW during these dives?

I have been CO2-toxic on a few dives -- the headache is incredible, and the nausea is bad, and it doesn't resolve right away after the dive.

Hi, Tiny!!! Welcome to ScubaBoard!!! :wavey:

Sorry it was this that brought you here.

This is a technical info link: CO2 Retention

If you search ScubaBoard, you will find a lot more info. TSandM can help, too. She's great at explaining things.

Here is an SB link: http://www.scubaboard.com/forums/ask-dr-decompression/372326-co2-retention.html

Lynne nailed what sounds like the most likely cause of the symptoms you describe and the possible reasons that might be causing them. Please keep in mind that this is an internet forum and that these are only our opinions based on what you have told us. I have experienced a CO event as Lynne described. Mine was with my own equipment, which I know how it has been maintained and used. The root cause for me was my own stress level on the dive which got greater and cycled into the CO retention.
Equipment and what you are doing on the dive, or your comfort level for the particular situation you are in are probably the most important factors to look into on the dives in question and then prepare for upcoming dives.

Hank658:

Lynne nailed what sounds like the most likely cause of the symptoms you describe and the possible reasons that might be causing them. Please keep in mind that this is an internet forum and that these are only our opinions based on what you have told us. I have experienced a CO event as Lynne described. Mine was with my own equipment, which I know how it has been maintained and used. The root cause for me was my own stress level on the dive which got greater and cycled into the CO retention.
Equipment and what you are doing on the dive, or your comfort level for the particular situation you are in are probably the most important factors to look into on the dives in question and then prepare for upcoming dives.

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Bit of confusion here. I think you mean CO2 (carbon DIoxide)

Dang, missed a 2!! Yup ianr33 you are right, CO2, not CO. That's a whole different issue!! Thanks for the catch!

Tiny, some people try to skip-breathe (inhale, hold it, exhale, hold it), or they breathe very shallow and quick, and this is what causes you to retain, instead of exhaling, the CO₂.

Could you describe your breathing routine for us?

When I was a was a new diver, I would suffer headaches and a bit of queasiness after each dive here at home (on the deeper side of rec limits), though not to the extent that you describe. I would have to sit on deck and not move while sipping some ginger ale or something for a few minutes. I wasn't skip breathing or breathing rapidly, I was very relaxed underwater. I did not have the same issue on shallower tropical dives.

I naturally do almost "yoga breathing" while diving, so I focused on almost exaggerated exhalations on my ascent. I also started doing deep stops/very slow ascents.

No more headaches.

I'm also very careful to be well hydrated.