Dizziness after sex

Last night I had sex more then once with new my boyfriend probably around six times his not exactly small and his the biggest I’ve had. Anyways he penetrated pretty deep and it kinda hurt so we had to slow down and change positions to se what worked best for me. But even when we did I still felt so so dizzy and lightheaded. Is that normal? Even this morning before he left for work I’m lightheaded again after having lots of morning sex. I’ve never had this problem with previous boyfriends so what’s going on.