Sex problems

Any suggestions on how to handle this. I have been with my bf 3 months now. And we had sex once. It was too fast for me though and we decided to wait until we said I love you. Well we said I love you now. But Im still not ready. I am so attracted to him and I get horny and wanna do things but I always chicken out. And if I did it i would probably cry and be upset afterwards. I just have very weird feelings with sex. I don't understand them. I was almost raped a few years ago but i managed to get away and ive been used just for sex a few times and that upset me. But I have also had sex with someone and we both really caree about each other and it was great. The last time I had sex with another guy and before him I broke down crying in the middle of it. Idk whats wrong with me or how to fix it. Any suggestions?