Jenny,
The modern workplace is not always fair...or legal. Unfortunately, that is a lousy fact of life.
Your first "job" should be to take care of your health and stabilize your lupus. You might consider doing something else where you can work part time or even work at home to relieve the physical demands and stress of working and commuting. I have MCTD (lupus, scleroderma and polymyositis) and PM totally crippled me so I did not have a choice about working and had to rely on my wife to continue working (we are both past retirement age). Fortunately I was able to get SSDI and will be on SS soon which has allowed me to work on rehabilitating. My problems were under control but PM took 40 lbs of muscle and left me totally crippled.
2 years later I have returned to independence and feel normal and can work a little. Having a chronic or serious disease changes our life and our relationships and each of must adapt in the best possible way. My way was to work on rehabiliation and try to return to normal. It has helped me and my wife is like a new person now that I am "back."
Sorry you are having these problems but some battles are not worth fighting when there is a more important one to fight.
Bill