Frustration

So I'm gonna vent a bit. So I've been with the same guy 5 1/2 years we have kids together, we split finally. I have his oldest child as well and take care of her. My grandma has financially helped for a while since he has quit jobs, and put us in holes, I've worked on and off. My mother had screamed and complained about every little thing I do wrong. She reluctantly let me live with her and since it's been chaos. Screaming and yelling at me over everything, house not cleaned right, my toddlers having toys on her floor, my toddlers trying to love on her. If I ask for the slightest thing, ride to buy groceries, ride for Dr appointments, to watch the kids while I shower. She screams at me that's she's too busy and will wait till we have nothing much to eat then she goes and blows all the food stamps on junk and not make meals. I recently decided going back to school would help and better our lives and told her and she told me to forget it I already tried that before I had kids and failed, to go get a job and be a mom that mom's don't have time to raise kids and go to school but she did stna training a few years back. I told her I got a job(they ended up not hiring me) she had bitched I needed one to get out of her house, and then when I told her I was sure they were hiring me had told me they were gonna, she rolled her eyes at me and told me how the fuck was I gonna work cause she sure as fuck wasn't watching my kids and how would I do that and be a mom and go to school? Just like school situation apparently her check bounced for high school fees years ago, and they need 147 to release my transcripts to college of my choice, she was like oh fucking well not my problem, I'm not fucking paying it best get a job....I have tried to please her and I can't, nobody gives me breaks with my kids, they all scream that I need to lose weight be healthy so I don't die early but won't give me breaks to take a day to myself.Anytime I ask for that I'm told again, I'm a mom quit bitching if I wanted time to myself I shouldn't have had kids. It's always being told I'm a mom and mom's don't get breaks to suck it up, that I'm just selfish and expect it to be handed to me. I never imply or say that but when I can't sleep, or I'm having days of depression and I'm screaming at my kids because I just want a day away from them, I'm yelled at for being a bad mom for going outside away from them or letting them run around in diapers and feeding quick easy junky food. Is this how it's supposed to be? Because I'm on the verge of a mental breakdown I can't afford :(