Hey man, I can definately relate to what you're going through.
I suffer from IBS - Irritable Bowel Syndrome. And as a result i can get the most crippling cramps from time to time. This is generaly controlled by medication, However it knocks my confidence every time i get it. This wasnt helped when i was working for a low cost airline as cabincrew, I got food poisening once on a flight. Most miserable experience ever.
Ever since then when i felt a bit dodge, i'd automaticly start worrying that its going to happen again, This caused a hell of a lot anxiety and am only starting to recover from it now. I put of training at OAA when they offered me a spot to recover fully.
My advice is to go and see a counceller. It does help, especially with techniques to calm yourself down if you get into a panic attack. Its worth having a look in to.
Hope things get better for you