CALM NERVES PLEAES HELP?

First of all, stop studying immediately. Stop practicing! Forget about tomorrow, go out or watch tv. Don't look at anything related to the exam until you are in front of the piano. And from now on, try to learn meditation and breathing correctly, that helps very much. Inhale through the nose with the mouth closed and exhale smoothly through the mouth. Let the arms hanging very relaxed. By the way, a cup lime blossom tea is very useful.