Jenrox, you really need to see your rheumy ASAP and if you can't get in to see your rheumy, see your primary care. It sounds to me like you must get these symptoms under control before dehydration sets in, so you may even consider going to the ER.
Like Lynnwood, I've been on CellCept with no noticeable side effects. It's the best drug I've found to date.
Please seek help Jenrox. Love, Butterflake