I have also been diagnosed with both. I also have RA, and sjögren's syndrome. I am currently in the process of switching rheumatologists, as I also show symptoms of SLE, such as hair loss, scalp problems, skin problems, and organ involvement.
I don't think I know anymore which symptom is from what. It is enough to make you bonkers.
Feel free to vent to me anytime. I am a great listener.