Hi.
There are many situations that--by their very nature--inspire anxiety. Even professional musicians who must perform in front of audiences feel it. It seems as though your anxiety is quite extreme, however. I imagine that you get even more nervous when people laugh at you, and that this issue is really affecting the quality of your life.
Here are a few things that you might want to try. Some you can do yourself and others will require professional assistance.
Anxiety, particularly around performance, can sometimes be decreased by performing meditation or breathing exercises. Some people use visualizations, in which they anticipate what might go wrong and then picture resolving the problem successfully, to decrease their anxiety. Hypnotherapy uses a variety of these techniques together.
Psychotherapy, particularly cognitive therapy that focuses on changing negative thought patterns, has also been shown to be effective against social and performance anxiety. A therapist may be able to teach you some of the coping techniques above. Once you know them, you can use them whenever you need to.
There are also some prescription drugs that work on social anxiety, but they are usually prescribed in combination with psychotherapy. If you'd like to investigate this option, ask your parents to take you to a doctor who can perform a thorough evaluation.
Take care.