Passing a school exam is not the end of the world! I am sure you have some strong points. Try to focus and build on those. Remember that many great persons in history were not able to do well at school. It is also possible that you can do well, but are simply not appearing for the exam out of fear. The best option for you is to get professional help as soon as possible. Try to contact a school counsellor, or a psychologist or even a telephone helpline. It is possible to reduce or even remove the fear by proper counselling and psychotherapy. It is not your fault and many people are prone to such fears. Get emotional support from your parents or friends.