I forgot to mention that severe fatique was one of the main symptoms. I hope you get to feeling better.
You could be having a reaction to the drugs you are taking. You need to research side effect of the meds you are taking. I recently found out that I am allergic to Sulfa drugs (Bactrim DS is one of them) while being treated for a UTI. One of my many side effects early on was severe lower back pain, flu-like symtoms that included sweats, achiness, joint pain, abdominal pain, rash on legs and a ton of other symptoms.. I only took it for 3 1/2 days, but paid for it for 5 wks after taking it. In my opinion it is a horrible drug. I could barely get out of bed during those 5wks the joint pain was so horrible. A website you could look at is http://briandeer.com/septrin/bactrim-pdr.htm
It sounds like a kidney problem or urinary tract infection. See what the urologist says. You could also see a nephrologist, a kidney specialist.