Is it possible I have arthritis, diabetes, or fibromyalgia?

All three run in my family, and I’ve always had weight problems due to my really bad metabolism (put on a lot of weight when I was about 5 after my dad left due to stress eating). The past few months, I was diagnosed with Asthma, and have been having increasing aches and pains in my back, joints and muscles. and a hard time staying awake. My doctors don’t seem to be any help, always telling me I need to just try to be more active, despite the fact that every time I try to go for a walk or do anything active I nearly pass out and am too tired the next day to move. (I used to walk 2-3 hours a day, but I just can’t anymore) My weight has also been fluctuating. I had dropped 110 lbs, but in the past six months have put back on 50 and can literally feel my body, belly, face and chin swell every time I eat for several hours, and I seem to be gaining a few pounds a week even though I eat very healthy and try to be active. I suppose it could be stress (I’ve had literally the worst three years of my life), but it’s getting worse and worse every single day. Anyone have any suggestions? I have a doctor’s appointment tomorrow, and I’m honestly thinking of demanding that they do literally every possible test to see what’s wrong, but I doubt anything will be accomplished.