The first thing you need to do is relax and think simple. As long as you are well prepared for the exam, you should not be nervous. You need to think about how much you have prepared for the exam and reflect on these things. You have to keep in mind that, it is your effort that will help you out and not being nervous. Do something relaxing like taking a walk, long bath or have soothing food, to ease the situation.
Don't worry! Just memorize the amendments and make flashcards. I have the Consttution Test on Thursday and im scared too. Im gonna relax though but still study. I need an A+ on it because im a smarticle and i need a's to live. Don't worry, be happy!!!!!!