The next tournament you will sit at the board, smile to your opponent, feeling happy that you have the opportunity to play a further game. The guy in front of you is not your enemy, it is a buddy who also loves the game and is ready to spend time with you playing an interesting game. You will give your best, that’s all, doesn’t mater if the guy is stronger or weaker than you. And the result is not the most important thing in this hobby. It is great to win, but better is to feel joy during the game. And by feeling joy you will relax and play better chess...and win more often.
Good luck!
I always get stiff during tournament rounds and I get nervous that I'm going to loss. Then I look at my time and notice that I feel much worse. I take some breaths but that doesn't help. Any Ideas on how to calm yourself down?