Your performance is to make people take a good look at you. If people don't pay attention to you, will your performance be successful? So seeing everyone watching you intently is waiting for your wonderful performance. It's a kind of support and encouragement for you. You only think that I will play better and don't spoil everyone's fun. This stage is for you to make good use of, but you can't help watching the audience. It is very important to relax naturally. Take a deep breath before performing on stage, breathe slowly for 13 times, and then come out with a smile, so you won't be nervous when you stand in the middle of the stage. Maybe you are inexperienced, the key is to remember to take a deep breath and call your heart for a long time to calm down.
The reason why nervousness causes abdominal pain is that the lungs and the large intestine are on the surface, and the heart and the small intestine are on the surface, so the abdomen will feel pain when the lungs are panting. It is not important whether the performance is successful or not, but it is important to try your best and relax! Let nature take its course and you will overcome the obstacles in your heart.
I wish you a complete success in your performance!