HELP. LOW SEX DRIVE ????!

Diana
So I've been talking to this guy for a couple of months and he is so fine ' ! I'm very attracted to him, but when we finally had sex today, in the middle of it I GOT DRY!!!!!  WAS SO EMBARASSED I didn't know what to do.. any ideas on why??!! 
It scares me but I always have a high sex drive so idk! I just started a birth control that I've been on about a month now .. I'm really hoping it not that though .