It's probably pretty rare but some antibiotics have been known to cause nerve damage and impair sexual ability - Floxin is one I've heard that can do it. Here's one man's account of his wife's run in with it
Were you able to have a repeat urinalysis done?
Problems with sexual responses or orgasms may stem towards a psychological cause apart from physical factors. The urinary tract infection by itself may not cause orgasm problems unless there is associated pain, redness or discharge in the genitals that may interfere with sexual enjoyment. In your case, you may still be worried of having the UTI and this may deviate your focus.
Have a repeat urinalysis done just to be sure.This will also allay your fears and concerns.