Can you get your Period while pregnant?

Ok. So me and my girlfriend had unprotected sex. Yes, i know, it was very stupid and I regret it so much but I can't take it back now. She got her period but she says it isn't right. She has cramps but the blood just isn't right. She also said she was having sharp pains in her stomach for about 2 weeks. I'm a little nervous. I didn't ejaculate, but i know theres still a possibility. If she got her period is there any chance? And please don't just reply and give me grief because I was stupid and has unprotected sex. i know I was very stupid, and I regret it entirely.