URGENT!

Patient: Good Day Dr. Pfeiffer, I am here to ask you something that i am slightly worried about. I am 18 Years of age and my Girlfriend is 17. We had intercourse Saturday. Tuesday night she said she went to use the restroom and saw a light brown spot on her underwear. She was worried and went to sleep the same night she called telling me her period is here , is it possible that she could be pregnant? ohh and yes i used protection.

Doctor: