I don't really keep track of how much beer I drank but I woke up this morning and it was all gone. My gf had a little mark on her and claims it's from me but I don't remember it.
Do you think you could have hit your girlfriend?
Maybe. We were playing some card games on the table and she cheats a lot.
Even if your girlfriend cheated in a card game, hitting her is abusive and should not be tolerated. You should apologize to your girlfriend and vow never to let it happen again.
I just did it because she cheats.
Hitting your girlfriend because she might have cheated in a card game is not an appropriate reaction. You should never hit or abuse your girlfriend for any reason. I think you need to work on your violent tendencies.