33 weeks pregnant and developed a cervical infection

I am 33 weeks pregnant. Last night I went into the hospital with contractions every two minutes. I was 45% effaced but not dilating. The nurse said that my cervic was very red and irritated with little white spots. They gave me an IV with antibiotics for a cervical infection as well as fluids for dehydration. They also gave me two doses of Nifedipine twice while in the hospital. When they sent me home I was still having contractions every two minutes. They gave me a prescription for Nifedipine, antiobiotics, and lortab to ease the pain of the strong contractions. This is my second pregnancy, should I be concerned with being 45% effaced so early even though I am not dilated? Also they never gave me information regarding what type of cervical infection I could have. I am to call the dr. office this week and get the results from the culture. What types of cervical infection could cause contractions. I have only had one partner and am not at risk for std's