white blood cells in urine...

I got a UTI two weeks ago (shown by nitrates in urine)...
I was given a 5 day course of trimethoprim, then went back a week and a half after the first symptoms, and a dipstick showed I had keytones, and protein in my urine... I was put on metronidazole (whilst waiting for the urinalysis to come back) as I am allergic to penicillin... the urinalysis only showed white blood cells and "organism" the doctor said it may be the sign of a partially treated infection... and i should carry on taking the metronidazole - any advice or thoughts on what to do next...