Over the past month mostly all of my back teeth have crumbled away sometimes i'm eating them and don't even know it . scared of the dentist?

You're too young to: Have your teeth crumbling away. Please do yourself a favor and go see a dentist. His / her intention is to help you and not hurt you. There are many effective anti anxiety medications that can be employed to help you. The first step is to make an appointment and express your fears when you get there. Hope this helps.

See a dentist: Eating teeth isn't going to hurt you. If your question is, is it alright to not see a dentist because you're scared of dentists. I would say, see a dentist.

Fear of dentist: Well, you seem to have extensive decay. You need to approach a dentist and talk with him to get reassured. Especially in a case like yours you must realize that you will eventually have to see a dentist and have treatment or you will suffer serious consequences. Laughing gas or sedation can help a great deal.