Hello doc, I am 19 years old, and I am currently on birthcontrol. These past couple of weeks (right after my period was supposed to end) I began having very sharp knife-like pains in my lower abdomen/uterus part of my vagina, along with heavy brown discharge. I had unprotected sex (my boyfriend has no STD's, 100% sure) the day after I thought my period had ended (my discharge was normal) and the day after that I had some red blood spotting, and that is when the pain began along with the brown discharge. Help?