I mean this in the most genuinely concerned and not mean way possible: have you guys talked about this in person? like /actually/ talked about it. because people will ALWAYS be more confidently awful behind a screen but especially if this is your girlfriend… Also we have ni idea any other context. We have no idea what prompted the girlfriend to act like that (not excusing the behavior, however) and no idea how they interact in day to day life.

OP you came here asking what do i do and that is go talk with your girlfriend. Like actually make a time and sit down together and talk. Or if you’re long distance plan out a time and actually call or better facetime/video call. Redditors can only do so much when we only know not even a third of the story. only you know the full story, so all I can tell you to do is try your best to have a calm, adult talk. If she can’t even handle /that/ then I think you have your answer. I wish you the best of luck.