If im taking nitrofur mono for uti why does my vagina smell i had a pap, doc told me i didn't have bv, std, yeast infection, but i had white thick dischar?

See below: It's likely that the antibiotic altered the bacetrial flora causing the odor.

Vaginal discharge : If all tests for infection were negative, then the thick white discharge is a normal, physiologic discharge.

BV anyway? Trich?: Bacterial vaginosis is the most common cause of strong vaginal odor, especially if it smells fishy. BV is overgrowth of mostly normal vaginal bacteria. Trichomonas, an STD, causes similar odor. BV can be hard to diagnose, and trich is often missed by the most common test, exam of fluid by microscope. Ask your doc about rechecking for BV and perhaps the newer, much more senstive DNA test for trich.