when you're worried about something your brain will blow it out of proportion, so it's easy to feel like it's the end of the world. just remind yourself consistently that no matter what happened, it's just an exam. your mind is your biggest enemy, no matter how you did you'll subconsciously think of everything that might've gone wrong making you think you did far worse than you actually did. just keep reminding yourself that your thoughts are not reality. you don't know if you got it wrong. you don't know if their answers are right. you don't know if you failed or passed, so there's not point in stressing yourself out about it now. it's over, that paper is out of your control now. keep reminding yourself of the facts, not your feelings. the facts are that you have no idea how you did, you might've done really well, you won't know until results day. focus on the future, distract yourself, take a break and work on your upcoming exams. but remember, it's completely normal to be worried as well! almost everyone feels this way after an exam, it's just part of the natural stress that comes with it. good luck