I Have A Nasty Bladder Infection As The Nurse Said.

I have a nasty bladder infection as the nurse said. I had blood in urine since January 1. Thought it was from intistitial cystitis. Anyway started taking macrbid wed pm and prydium but I feel no improvement. Should I switch to Bactrim? Culture is not back yet. Thank you. I have never done tthis before asking a question that is.