Since then and I get panic attacks when I see the blue or feel cold.
Sounds to me like your survival instincts have kicked in a bit later than they should have, and a bit more forcefully than necessary.
Have you considered consulting a therapist, or somebody else that has real professional experience with this sort of thing? You might get through it on your own, but where I live an hour with a therapist costs no more than a boat dive, and it won't injure you or cause a panic attack no matter where you're located. An experienced professional might offer insights that we won't, and may even bring up issues that aren't related to to diving.
If you do work at it on your own, you've already gotten some good advice. Panic is a natural, if not ideal, response when you're in serious danger and feel you don't have (enough) control over it. If you're having panic attacks on easy dives where you're in control and not at risk, I'll assume it's because the past experience still prevents you from feeling that you're in control or that you can stay in control. Bob's story about the jellyfish is a great teaching example. By focusing on one easy task the diver accidentally accomplished a similar task that she didn't think was easy. Once she'd done it that time it remained easy because she believed it was easy and that she could do it.
Before you even get in the water you can do some dives in your head. Just relax where you won't be disturbed, close your eyes, and imagine an easy dive in as much detail as you can. Check and assemble your gear for real, then imagine putting it on, getting in the water and descending, and so on. Imagine doing some safety drills and checking your gauges. Imagine feeling warm, weightless, and in control of your dive. Imagine a slow, controlled ascent, and don't forget the safety stop. After doing that a couple of times try some easy dives in a pool or very easy open water and include a bunch of easy tasks that will give you something to concentrate on, instead of thinking about possible problems. Standard scuba skills seem like a good choice for the first tasks. Flood and clear your mask 10 times. Take it off, put it back on, and clear it 10 times. Switch to your octopus and recover your primary reg (including the drop the shoulder and sweep for the hose routine). Hover at a fixed (but shallow) depth while remaining horizontal for 5 minutes at a time. Find a hard bottom at 10 to 15 meters and do a very controlled descent, just as you would with an ascent. Try to hover 1 meter off the bottom while remaining horizontal. Do some simple navigation stuff. 15 fin kicks or 30 seconds then turn 120º, and repeat twice to swim a triangle back to your starting point. Swim some squares, and a pentagon. The tasks will hopefully prevent you from worrying, and at the same time they should help you believe that you've got the skill to be in control of your dive.
Advance slowly, and don't try to make big jumps. The primary goal is to stay, and feel, in control at all times. Not having panic attacks should just be the free prize that comes with feeling completely in control, rather than an itemized goal.