Dont worry, the chances are very slim. How often you heard a virgin girl pregnant?
Buy a few pregnant test kit to test la.
Ask her not to worry too much. Try ask her to relax in her life. She is too stressful, ask her stop all unhealthy food or drink etc coffee.

It happen to me before, her period didnt came for 2 months. That time she just switch job. Very pressure, wake up early, sleep late, no mood to eat, drink lots coffee. During that time i also scare, and i test with her, bring her to doctor. Charge me RM180 just for the same advise i wrote and no any vitamin or medic given. What to do?

--- You give her sperm, she give you baby ---
Actually is quite worth wor!? hahaha...relax, dont panic togther.