Wasn't her mom taking her to the doctor?

I'll bet she never told her mom and this is all some elaborate drama. Truly.
So she would have just gotten off her period when you had sex? She wouldn't have been ovulating yet.
She cannot have any symptoms of pregnancy since her body wouldn't even know she was pregnant at this point. It is just silly.
Rest. Relax. Breathe. She is freaking out and causing herself to think all kinds of things.
In 10 days, go to her house with a pregnancy test and sit with her while she takes it.