Since my mid 20’s my physical health declined to the point where I was almost bedridden. Saw a Rheumatologist and he diagnosed me with Fibromyalgia and Chronic Fatigue. Those illnesses are common co-occurring with mental illness. Now I am a bit better but cannot do much exercise or I will crash afterwards. There are few, if any, treatments that work. I despair too that I have lost my physical health. I am 41 now. Maybe try to get into a Rheumatologist once you have the money. With mine helping me me I have gone from bedridden to mostly functional most days unless I have a big flare up. Good luck.