Why does my mom get so freaking drunk?

last summer she would get drunk every night until my dad said he was going to leave if she didn't stop. this summer she's been doing it again and it's been bugging ME more than my dad. it's like she can't stop after she has one drink and eventually she ends up slobbering drunk after a whole bottle of wine. i try to tell her to stop, but all she does is say "leave me alone" over and over again as if they're the only words she knows. it bugs the hell out of me!!! she'll start slurring her words and whenever she tries to grab something, it takes her forever to get a hold of it. what do i do???