What Causes Vaginal Bleeding After Sexual Intercourse?

I had sex this morning and bled during or immediately following, not sure which. It wasn't particularly heavy, but enough that I thought i started my period, but turns out I didn't. I have been absinate for basically 8 months, and we have had a LOT of sex since Friday. is it possible I had some internal tearing that I wasn't aware of and this is where the bleeding came from? This has never happened to me before.