You arn't stupid 
-squishes-. Why would you class yourself as stupid just because you don't have much experience with this. It doesn't sound at all stupid to me. Don't be sorry =))
I just wanted to quote something you said.
"i'm sure he will think i'm being stupid cuz i weight too much for it to be problem anyway."
Now that is a common mistake most people make! And i hope he dosen't do the same to you, should you choose to tell him. The weight factor shouldn't be the thing that defines weather your struggling a lot. Or even to say you have some sort of eating disorder. It isn't about how low/heigh weight is. It's what goes on up there...In your head that should be the thing that is really focused on. By reading you post written here already sounds like you have some of the thoughts people with eating disorders have in early stages. I DO think it's worth telling him about how your feeling though. Maybe he could help before it yor thoughts progress more. & if you truely do feel he'll think your being stupid (some therapists are arses) then maybe take a trip to your GP and see your doctor or a nurse there. It's deffinatly not worth leaving and you shouldnt have to deal with them alone.
Caz
xxxx