Fibromyalgia, SLE Lupus, Weight Gain, Shortness Of Breath, Heaviness In Ribcage, Suspected To Be Sliding Hiatal Hernia. Suggestions?

I am 54 yr old, I am 5 ft 3 in tall. I have fybromyalgia and SLE Lupus . I have gain about 23 IL over the last 6 mo, I don t know why, except I have been feeling bad and been under alot of stress . My stomach is alful looking it s like it just blowed up too. I am retaining fluid, I work at a desk sitting down for 9 hr a day. I have many ups and downs with all my problems of course. This big stomach and being short of breathe is a big worry for me. I get short of breathe doing anything, but it comes and goes. The dr check my oxygen level with the thing on my finger it s always 98 per cent,which is great. I am very worried about this. I bend over or when I lay down, or if I try to walk, anything I feel like there is a football in my rib cage. My clothes feel like they are cutting me in half all the time. I have been told I have a sliding hiatial hernia . I have lots of trouble with GERD also. I am concerned about this big stomach and the breathing. I want to loose about 25 lbs but it s hard to do anything . Can you please give me advise.