Regardless of the 'why' of how you feel...if you're feeling unsafe or that you might harm yourself get help like tell someone or go to an ER if need be. I just know even if you are just 17 feeling so low suicide is on your mind is a serious thing...but if its just one of those passing feelings and has diminished since you posted this...perhaps maybe trying to get into some therapy though with the situation with your mom might be hard getting into that if you at all depend on her to get places and set things like that up. Do you just live with your mom or do you have a dad around that's maybe less drunk than your mom? Also don't know how the teachers/staff are at your school if you're in school or if they potentially have a school counselor that could help but maybe worth looking into.

Also you're certainly welcome to continue posting here and vent about stuff bothering you.