I can relate to this. I can procrastinate on a professional level. I should teach a course on procrastination I am expert. But I don't feel good about it and on some level it is a form of self abuse. So I have to analyze why am I doing this. It is about fear. Fear of failure, fear of ridicule, fear of rejection. But the feelings of disgust I have for myself in all actuality are much much worse than whatever fear it is I am avoiding.
It's easy to sit here and say... hey just face your fear and take your exams, but in reality it's is paralyzing.
Take it maybe in small chunks. Study up say about 10 minutes a day on your exams till you have covered the exam material. You are better off attempting failure than not facing it.