I was recently diagnosed with a UTI. I have been getting UTIs since I was really young. I went to the doctor two days after I started having the syptoms and was put on Bactrim DS. I started feeling the side effects of the medicine a day later, with nausea and headaches. A day and a half after I started the meds I started getting a rash or something that looks like little white zits around the vagina and anus which are painful. I also started having pain in my back and in my glands. Could this be Herpes or another STD? Or an allergic reaction to something?