Bleeding

First of all, to make things clear I'm not a virgin. Haven't been for years. I've had sex numberous of times.
Well today my fwb was fingering me and he was going really fast. And I started bleeding. Not like period blood but like when you lose your virginity and there's slightly blood. And I'm just confused as to why I bleed??? I mean I've done so much faster and harder things but never bled.