I ve been having UTI symtoms for 6 weeks. I ve had 2 urine and blood samples in the last month and they all come back negative. I ve been given cephelexin and doxycycline to test it and it has not gone away. It burns to pee and my lower abdomen is always sensitive. I am a 61 year old man and am very frustrated. I am being treated for a herniated disc. My urologist thought it might be nerve damage and prescribed Nortriptyine which I took for 3 weeks and made me tired and weak but no change in the symptoms. What could this be,and is it safe to have intercourse with my girlfriend. She thinks it might be risky. I belong to Kaiser health in the LA area and feel there not doing a good job to diagnose what my problem is. Please help.