Sorry you're having trouble getting any kind of proper diagnosis. I was diagnosed 5 years ago or so with Lupus but just this week they've taken that back and told me it's Fibromyalgia instead as all my bloods are always negative except the very first set I had done. Not that that always means much really but is very very frustrating.
Re weight, I've been told to lose weight as well and even though I know I have to for my health it's way easier said than done! I'm not massive but am no stick insect either and excercising leads to lots of pain for me so it's a vicious circle. I just wish they'd offer some more support for losing weight when it's for medical purposes instead of seemingly thinking it's easy peasy!
Hang in there ~hugs~ x
Numpty:- (num-p-tee) dialect, chiefly Scot, ~n. 1. a bumbling fool: one who is intellectually challenged. 2. widely known in Scotland as an MSP (Member of Scottish Parliament).