There's nothing to gain over needless worrying, but lots to lose. Many things can lead to exam anxiety: Cramming at the last minute, getting run down, drinking too much coffee the night before (or the day of) the exam, getting wrapped up in other people's stress just prior to entering the exam hall, applying false logic (if I fail, then I'm a failure as an individual . . . that's not true) and negative thinking. Be more positive—you wouldn't hang pictures of failure and despair on the walls in your living room, why do you hang them in your brain?
Interestingly, a major source of anxiety comes from poor study habits. Proper study techniques can help bolster confidence leading up to exam day. A few lifestyle tips can make a difference when studying: (1) take light exercise breaks (a short walk to clear your head), (2) don't skip meals (your brain can consume up to 1/5th of total body caloric intake); and (3) stick to a regular study time (consistency pays off in the long haul). Above all, use practice questions to test your knowledge. It's all about practice and recall for most adult learners.