I'm not qualified to say what is wrong and while it may be apendicitis, she should definitely see the doctor. According to webmd.com -
Appendicitis is a medical emergency that requires prompt surgery to remove the appendix. Left untreated, an inflamed appendix will eventually burst, or perforate, spilling infectious materials into the abdominal cavity. This can lead to peritonitis, a serious inflammation of the abdominal cavity's lining (the peritoneum) that can be fatal unless it is treated quickly with strong antibiotics.
It's always better to err on the side of caution so definitely encourage your girlfriend to get to the doctor or ER as soon as possible.

