It sounds like you have some things you are worried about and your worries are affecting a number of areas of your life.  If you can get help for your self-esteem, it will help you to feel better in the other areas also. There are good counseling techniques that can help you with anxiety and with your concerns about your body.  You can also get help with shyness.  Your medical provider may be able to help you find a therapist or counselor or there may be a counselor in your school.  You may also be able to ask a parent or trusted adult where you can get counseling.  It will help to talk to someone who understands what you are worried about and will have ways for you to feel better.