UTI and pregnancy?

Brook • Trying for our first blessing since July 2014
I visited the doctor on Wednesday because I thought I had an uti. After testing my urine the doctor told me I had a slight infection going on. I was supposed to start my period on the 15th. My doctor knows we have been ttc for four months now but the medication he gave me says not to take while your pregnant or ttc. Could I be pregnant? Has anyone else's doctor confused a uti for pregnancy?