My advice: only think about the positives rather than the negatives. Imagine that you are preparing for a meeting, or you are going into a surgery, and everything will go perfectly fine. When you think negatively, you assume that something bad will happen. Giving yourself positive reinforcements is the best way to overcome stress, so that nervousness can turn into excitement. See your situation in a brighter light, no matter which way you look at it. If you are nervous, convince yourself that you are excited instead. When you feel excited or very enthusiastic about something, you feel good. You do not feel nervous, self-conscious or unsure of your abilities. That way, even rainfall can be turned into sunshine. Throw your gloomy hopeless thought away and replace it with one that gives you hope and peace.