Im bleeding...?

This isn't the first time my boyfriend and I have had sex, before him I was a virgin. So granted it's only been maybe our 8th time or so. Last night as he entered me I felt a pop, like when you get a massage and they roll over from one muscle to another... we go pretty hard and fast... but anyway later that night I got home and noticed I was bleeding like as if I started my period. I kind of freaked out, I told my boyfriend.

This morning it stopped but I'm kinda freaked out. Was it just too much friction or could it be something worse?