Why do I bleed?

I haven't been a virgin in over a year and I've only been with my boyfriend the whole time. recently, the past three times, I've bled during and after intercourse and none of those times was I on my period. Why is this?Why do I bleed?
If this happened all three times, consecutively, don't mess around, get thee to a doctor NOW! ! ! ! It could be a symptom of a number of problems.....
ANd ignore these perverts that are gonna answer with filth about 'tha ruff stuff'! ! !
Make sure you are using a lubricant -- KY jelly. If your still having problems, go see an ob/gyn...