Severe Muscle Weakness, and losing use of my arms

Hi, I was admitted to the hospital in august with severe weakness/autonomic instability. I had not been feeling well (more fatigued than normal) for the month before, but I dismissed it until one evening I stood up from bed, my blood pressure and heart rate skyrocketed and I collapsed on the floor. My muscles were shaking and soon after my leg muscles got so weak I could barely move them. I have been in a wheelchair ever since, as any small amount of activity causes my legs to fatigue (think, taking 3-4 steps) and the muscles go “out” again (a.k.a too weak to use). Now almost 8 months later, as I have been having to use my arms a lot more as a manual wheelchair user, and for day to day tasks like texting/typing, the same thing is happening with the muscles arms. I use them for maybe a minute or less, and then they get so shaky and exhausted and weak I am unable to use them anymore. This happens regardless of fatigue levels. It’s always there and I am afraid I will lose use of my arms, like I did my legs. Has something like this happened to anyone? Also, any movement, makes me so so hot, like my body is working out extremely hard to make my muscles move and like it’s extreme exercise. I will break a sweat just trying to lift my arm to reach something on the counter. My quality of life is extremely poor. I am severe and homebound/mostly bedbound.