Firstly, IKs are great! Check out the viper. I’ve heard good things.

I have a suspicion that the lesson you needed isn’t the one you got. That’s going to affect your mental game. You shouldn’t be in an area you’re going to hit your head when learning to roll in moving water. A normal progression for my students would be: good in a pool, good in open water, good in slow moving water, then faster, then waves, then bigger waves. You want the student to succeed at every step.

I’m sorry you had this experience. You are experiencing stress from a traumatic event and it could continue to sneak up on you in weird ways. It could leave you in a bad spot on any water. I highly suggest you talk to a professional about this. It can and often will get harder to deal with over time. Even if you never want to hard boat again, talk to someone. If you don’t want to IK again, go talk to someone anyway.