Severe Kidney Pain???

Hi I'm a 26 yr old woman with Lupus, Rhuematoid Arthritis, Fibromyalgia, and Degenerative disk disease. I was recently told by my rhuematologist that i have a UTI and was given Cipro. I've been taking it for 2 days now, but the pain in my kidneys (mailnly my left one) is killing me. I've been unable to sleep, stand, sit, walk, or even drive without intense sharp pain. I've done some research on the subject, but it hasn't told me anything new.... When should I consider it bad enough to go to the hospital? Thanks in advance :)