Technically drinking any amount of alcohol that makes you drunk is bad for you, but unless you want to become an abstainer you'll have to drink socially.
How much is too much? Well, I have friends that party twice a week and share a whole bottle before getting the drinks in the club downtown, of course, they get pretty hammered, also, some relatives from the older generation definitely drink a little bit too casually. I'd say it's too much when you acclimate to a rhythm like that, just because you're partying more than usual in your holidays doesn't mean you're going to have a problem.
That said, remember to hydrate (preferably before, during and ofc after) drinking and try to eat something with your drinks if you don't want to lose it, personally I drink socially like once or twice a month and have figured out the point I want to reach before calling it quits so the hangover won't be too bothersome. Have fun~