I have a 6 month old Pitbull and for the last3 days he hasn't been eating and is barely drinking and he I very weak and won't let me to close to him. I have called a vet an made an appointment but until then what should I do?

How soon is your vet appointment?
Your dog needs to be seen yesterday.
Call your vet back and stress the urgency of the situation, if that can't get you in immediately, call elsewhere.
Three days without eating or drinking is too long.

I agree with Lady Sam. It's good that you're going to the vet, but this can't wait until tomorrow, or a few days from now. You need to go in now.

Do you have an emergency vet in your area?