I Have Urge To Urinate Frequently And There Is Usually

I have urge to urinate frequently and there is usually not much there. As soon as I leave the bathroom, the urge to go is there again, usually a sensation in my genital region. I thought I had a UTI, but the urine sample showed no bacteria, although there was some blood present. Dr. gave me a an antibiotic, I felt great for
3 days, but now the symptoms are back. I am not incontinent, I never loose bladder control or leak.