I Held My Urine About 3 Weeks Ago For A

I held my urine about 3 weeks ago for A very long time until it started to burn. Now I hear gurgling sounds in my abdomen and I feel like there is liquid in it. I also have a reduced weak stream of urine and feel like my bladder is constantly full. I went to my doctor and he prescribed antibiotics thinking it was a bladder infection. The symptoms went away for a week, but now they are back again. I also experience extreme pain in my lower abdomen when exercising. What do I have?