I Was Prescribed Sulfamethoxazole-tmp For A UTI And Have Been

I was prescribed sulfamethoxazole-tmp for a UTI and have been taking it prescribed 2 times a day for a few days now. The day after my dr visit I caught what i believe to be a really bad cold, possibly strep with how bad my throat hurts, what feels like swollen glands, fever, chills - would this same antibiotic treat strep or should i return to the doctor for a cultre for strep?