No, you are not crazy. Is there anyone you can talk to? You speak of wanting to be understood. You may have to take the first step and find a safe person you can share your worries with. If you feel you have absolutely no one you trust to talk to, please consider speaking to a counsellor; an individual qualified and trained to help teenagers. Sometimes, just by talking about your worries and concerns, you can release their power to create anxiety within you.

The pain in your stomach should be taken seriously. You might want to see a doctor about it. Good luck and all the best.