help!

So my boyfriend and I were having sex and then I realized that I was bleeding. I didn't feel any pain, it just kinda happened. This is not the first time we've had sex and I am on the pill and most of the time use the "pullout" method rather than a condom but don't go without practicing one of these. I am still 9 days away from my next period. Is this normal? Does anyone have any advice?