No One Knows What to Do For Me

I have Lupus (SLE)... as a result I have to take often high doses of prednisone.  While I have to take it, it definately increases my appetite.  During these times I feel like I have a constant state of munchies.  Also due to the illness, I have almost crippling fatigue at times.  I keep telling myself.. oh just go out and exercise or walk or something, but I do it once and I am laid up for a couple of days due to how tired it makes me.  Doctors have told me that I must lose weight, but they forget to say how exactly.  One doctor even told me that I may as well get surgery.  I doubt I am even a candidate for this.  I would appreciate some advice from anyone who is going through something similar thanks.