Red flags, trust issues, and just rude in general. To be fair, it's understandable to be a little jealous or concerned that your significant other is cheating in the situation you described, but regardless the way she approached it is just straight up manipulative. It still seems possible they're fucking with you, entirely depends on their intonations that can't properly be described through text. But ultimately, talk to your gf about it, tell her how you feel and how what she did is making you feel currently, and if she can't understand that then idk what to tell you bro, might not be the best relationship to be in