Is this experiance normal in a new relationship?

[AnnaveGrengables]

I've started seeing this amazing guy, who really is everything I've ever dreamed of. We started having sex and it was unreal for the first few weeks, but then one day it just wasn't really good for either of us. Since then I haven't been able to enjoy sex like I used to, because I've been thinking about the time is wasn't great and if he and I get married will it crumble and the sex will never be good. We havent known each other for that long so maybe we rushed into it. Also, there are some times when we have sex that I can feel him, but I don't feel the way I used to during sex (ie. I can just feel him in me, it doesn't feel great.) Now I've been thinking that I'm a lesbian or something because I need clitoral stimulation to feel any pleasure during sex and when I don't get it I just don't want to have sex. He's an amazing guy and I really can see myself being with him, but thinking that so soon scares me, along with the thoughts about the sex not working and the thoughts about being gay! (Also, I've had bouts of HOCD before, but they went away when I met him. Since this sex issure started, they've been back.) How do I let myself fall for this guy and know I'm really into him?