sucky sex

sex is sucky. My boyfriend is about 5 inches and I am not big but when we have sex I feel nothing really. He's well in but nothing feels good. It makes me sad because I know people have these amazing reactions to sex and I feel like there is nothing going on. 
So I've tried to get him to take it slow like maybe I'm not turned on enough but I don't think that's the issue here. Is it me or him? Because he loves sex. He thinks it's the best thing since sliced bread. I just kind of let him have at it until he finishes. And he takes a while. But he knows I at least can't finish through vaginal intercourse but shouldn't I feel some type of pleasure at least? It just feels bleh. 
Sex just makes me want to cry because I'm so sexually frustrated.