What Causes Lower Abdominal And Back Pain Along With Vaginal Bleeding?

Hello, I am having lower abdominal and back pain. Went to see a doctor he said I have a UTI&prescribed ciprofloxacin to use in 7 days but today is the 3rd day I am using the medication the pain is still there but has lessened a bit and it is the second time I am seeing bloo and can feel it coming from the vagina. May you please tell me what the problem might be?