I am very upset. I don't want to eat or talk. I just want to live quietly in a quiet house for a while. What is wrong with me? Am I sick?

Your state should be mild depression. It will be very helpful for you to find a best friend to talk to. Now that you have realized it, you can take the initiative to seek outside help, or you can ask a psychologist or counselor to help you. Don't stay at home, go out more, so as to get rid of this situation as soon as possible.