helppppp meee

I've been recently having sex with a new man after my two year relationship has ended. It's been like non stop for the past two weeks. Absolute best sex I've had. But now I feel so crampy the last few times we've done it. It hurts so bad everytime he goes deeep. Could this just be because all of the sex?? I'm due to start my period in a week maybe that could be it? Worried.