Is it possible for you to take some kind of qualification which does not centre around exams? Coursework-based qualifications, perhaps?

I don't think there's anything wrong with you. Some people just really don't "do" exams! Myself I have a very weird history of being a great student and bombing exams, often because I enter the exam room and start throwing up/having seizures/one time my eyeball started to bulge out of my head. Eh!

Have you discerned what causes the anxiety? Is it a lack of preparation? Over-preparation? (Sometimes when you revise too much, it only makes you more aware of all the stuff you don't know.) Generally nerves about exams? Fear of past failures predicting future failures?