Hello there. I can understand your concern. So when did you and your girlfriend have unprotected sex? Which day of her cycle? Because certain days in her cycle are not fertile so chances of pregnancy are less. And why are you saying "my friend" when it's clearly "you". Yes bleeding is possible even if she is pregnant in a few people in earlier weeks . Take a urine pregnancy test at home. Consult a gynaecologist in person for further evaluation and management. And don't put your girlfriend in trouble by having unprotected sex, use a condom.