I feel like a horrible mother

Preface to this whole thing: I feel like shit about this and opening up about it is hard, so please please don't judge me. I know I need help, I just don't know where to turn, and need some direction.I would say 80% of the time I am happy, and patient with my children. Usually I will give warning after warning, being firm but not flipping my lid. But there are occasions, maybe once a week or once every 2 weeks, that I freak out, hard. It's usually over the dumbest shit.. whining is like nails on a chalk board to me and makes my skin crawl. So they whine over snacks usually. They will finish a snack and then my son (18 months) will stand at the cupboard and point to snacks and whine and whine and whine. My daughter (3.5) will whine about not being able to watch a show on tv, or going to bed, or sleeping in her own room, or brushing her teeth. I know these are all normal young children things and I know there are positive ways to say no but instead I end up getting in their face and screaming "STFU" or "why do you guys have to be such assholes" or "why can't I just have normal kids," the worst thing I have said is " that's it, no one appreciates me, I am leaving," this made my 3 year old break down and cry and beg me not to. I feel fucking terrible about it. I love them so so much and I KNOW I AM MENTALLY ABUSING them. I need to stop! PLEASE I am desperate.Steps I have taken previously: Taking antidepressants for roughly a month, made me not yell but also made me numb and not give a fuck about anything else, I stopped and still felt good for probably 6 months after.I sat down with my significant other and asked him to please keep me in check... I asked him to call me out and tell me I am wrong. He said he was worried about him getting the brunt of it. I told him I think him saying something would bring me back to earth... I just hulk tf out and cannot control my language or my actions and have noticed this happens 1000x more when tired or trying to quit cigarettes, as I am doing now.EDIT: typo via /r/Parenting https://ift.tt/2vcwTir