4 weeks levaquin?

A urologist prescribed 4 weeks 500 mg levaquin after an exam in which he was unable to demonstrate an infection. It went like this. Urine samples were ok. Then prostate message, then inability to urinate soon. He tried to get a sample of non-urine from the massage, and I think failed. He did say that my prostate feels infected in some way in a "rectal exam". I do have symptoms like burning, urinating sometimes too often and sometimes not enough. I have some doubts about whether I should take the antibiotic without clear signs of a bacterial infection, especially for 4 weeks. Is this reasonable?