I Have Had Uti In The Past. I Went To

I have had uti in the past. I went to the hospital and the test results were elevated white blood cell count. I was prescribed a medication but still didn't feel as tho my bladder emptied all the way. I went to a little clinic at a local pharmacy. I told the doctor, I usually take Bactrim ds. She gave me a 3 day supply. She sent my urine out and said there wasn't any bacteria in my sample. Still no luck. I'm confused now. My back hurts but I had an Mr I done and the results were a herniated lumbar disc...L1.