Girlfriend cheating redflag?

Anonymous
so my girlfriend is acting very strange and is really cold with me after meeting a dude in our class (he smokes weed, and she is also a smoker, pretty sure they smoke together). She always greets him with a hug but never does that with other guys and now she is acting stupid and she is always chatting with him while ignoring me.
So I already am 99.9% sure she is cheating but I would like some input from u guys.

thanks
Girlfriend cheating redflag?
2 Opinion