Got blackout drunk and went crazy, not sure if it’s something with me or alcohol

Don’t drink much but I have a decent tolerance for it. Went out drinking with my fiancée while on holidays and both of us got wrecked drunk, I blacked out and can’t remember a good portion of the night. We were both having great fun though, but on the walk home it’s like a switch flipped inside of me and I went crazy. Got really mean, threw my wallet and belongings away, and acted like a general scumbag.

The thing that worries me is that I’m usually quite a happy drunk. Been dealing with a good bit of stress lately but I didn’t think I had that sort of anger in me, I can’t remember ever lashing out like that.

My question is, did I always have that in me and the alcohol just brought it out, or was it the alcohol messing with my head?