USED FOR BLADDER INFECTION?

yesterday I went to my doctor feeling great for my yearly checkup, he told me I had a bladder infection, although the girl in the lab said my urine test showed no signs of infection. He gave me this perscription of SMZ-TMP DS. I took one pill and I have felt terrible ever since. I do not believe I have bladder infection. I have not taken another pill since experiencing headache, tiredness, and a car sick feeling. Is this drug for bladder infection?