What is an orgasm supposed to feel like?

I lost my virginity to my boyfriend and I love him. Sex I feel very intimate with him but I also feel during sex that the feeling is too much and overwhelming. I wanna like the feeling but I sometimes have to get him to stop especially when he goes too fast and about to finish. Am I being overstimulated? Is something wrong with me? Am I fighting an orgasm? I just thought it would feel more pleasurable. And I really dont like the constant feeling of needing to pee (I know I'm not). Does anyone have this problem? What is an orgasm supposed to feel like?