Hi.. I have had UTI for about 4 weeks now. Earlier I was prescribed cephalexin but doctor said it won t work as there was no bacteria in my urine. I took the medicine for 2 days and I felt better as frequency went away. I stopped the medication and it came back after one week with back pain and resistant to cephalexin.I got trimethoprim prescribed for 7 days, back pain went away but frequency stayed the same with cloudy and bad smelling urine.I went again and the doctor gave me nitrofurantoin and told to do ultrasound. Ultrasound was clear but frequency is still the same. I am on the nitrofurantoin medicine for 4 days for a 15 day course and it doesn t look like it s working. The more I drink water, the more I have to pee. Earlier I used to pee once at night, now I am peeing 3 times. I don t have any kidney, back or abdomen pain and my urine test results came back negative. Kindly help.