Advice?

Whitney
I was so excited to go in for my scan today. I'm 14 weeks. We saw them and I went back to talk to the doctor. The nurse told me I had clamydia. Which I thought would be impossible because I haven't slept with anyone except my boyfriend since we got together. So I immediately jumped to "he cheated". We've been together since October. I wanna know if you can carry it for that long and get pregnant also.. He was with a girl before we got together who is really nasty.. I thought maybe if he didn't cheat then he has had it. I've always been clean and I've asked the two other people I've been with if they had it at some point and they told me no. I don't know what to think or believe because I love him and maybe I'm just making excuses for him. He denies it completely. But he would deny it if the answer was in his face.. I just don't know what to do. I'm scared. He says im the one who cheated. I would never cheat. Here's my ultrasound.