Orgasms!

I know like everyone has posted at least once about orgasms so here is my turn lol. I've been with my bf for 3 years, and never orgasmed, or even was close. I know it feels like a buildup but I've never felt that. Even when he rubs my clitoris it get so sensitive that it's uncomfortable and I move his hand away...so I'm not sure what to do. I've never orgasmed by myself either. I rub my clit and I gets really sensitive and I feel a slight buildup and my body gets shaky...is that what it feels like to almost orgasm? Plz help thanks.