Great Sex

I hooked up with an amazing guy last night, the second guy I've ever slept with (I'm 17). he is very well-endowed and knew what he was doing so the sex was naturally mind-blowingly good. but the day after (today), I am incredibly sore. my lower abdomen hurts as well as the inside of my vagina. is this because he is larger and possibly bruised the inside of vagina/cervix area?? I have no idea what else it could be, help!