Sex is becoming a problem a year later?

Sa
So I was raped by my boyfriend (now ex) in February 2015. When it happened I was very drunk (I don't know if I ever said no because everything is very unclear to me) and my boyfriend knew I was waiting till marriage. I remember the pain and how he just finished and then passed out. But that's about it. I didn't report it or tell anyone and I stayed with my boyfriend because I was afraid no one would believe me and I wasn't sure if I'd said no. I kept having sex with him and our relationship turned abusive. I used to just emotionally detach when we did anything sexual and I spent a lot of energy suppressing everything and pretending it didn't happen and that I wanted it. I moved away for the summer (we were in university together) and then felt like I could walk away and I did. This happened a little over a year ago. 
Well I've been in a relationship with someone new since December. He's everything my ex is not. And I love him. We've been having sex for months now and I've never had an issue at all. Even the first time we slept together I was ok (but I think that was because he was so good to me and the sex was so different from with my ex). Well now I'm starting to feel empty again whenever I have sex with my boyfriend. Or I just feel overly emotional and want to stop. It's not that I'm not aroused or that I don't want to have sex because I really do. I'm fine throughout foreplay but as soon as we start having sex I start feeling awful. I just don't know what to do. I don't know if it's PTSD or if it's something else. Please help I'm so worried about these feelings.