Second trimester sex. This may be tmi

Sorry for the tmi if you think it is..

My boyfriend and I had some pretty hard and long sex earlier today.. and I'm not cramping, I'm not bleeding but my stomach is sore and I feel like I'm pulsating in my lower abdomen.. I was on bottom the whole time and we were face to face. It's been hurting to have sex a lot more lately, although I crave it like no tomorrow!! I just am scared and it's my first pregnancy. Help?