Bleeding After intercourse

I had sexual intercourse and it wasent my first time i been active for quiet some time , i went to the restroom and i noticed a little bit of blood i am in my last day of ovulation i am quiet concerned and was wondering what could be the cause of this ? My period is about to be here in a week , i am a healthy female and got no STDS or nothing like that , i am on PlAN B as well .