I just need a little guidance

So I had sex for the first time a week ago. I’m on the pill and we didn’t use a condom, he didn’t finish in me and he says he was never even close ( it wasn’t his first time but it was mine and we went really slow so I didn’t get hurt) now I’m having cramps and some pinkish discharge when I wipe. Idk if it’s just my period being weird ( it was weird the month before this is only my third month on the pill ) or if it’s implantation bleeding.