MY MOTHER IS DRIVING ME CRAZY

I'm a 22 year old full-time working mom to an almost 2 year old whom my mother watches while I work. I come home, get my son and go in my room. I usually steer clear from my mom.. I don't sit in the living room with her. I don't converse with her much due to the fact that she literally does not seem interested in things I talk about. She simply either ignores me or just barely says anything at all. Whether it be about my work day, me moving to California (where my girlfriend lives) etc... 
She knows I want to move. I plan on moving.
I feel it is also for the well-being of my son. Although she is an okay grandma, she belittles and undermines me. "Did you feed him? Why are you giving him so much water?" Asking me tons of these questions in a kind of rude way trying to make it seem like I'm a piece of shit mom. 
Well, I'm not 
I'm also not allowed to voice my opinion.. or that's when she out-bursts.. she will yell, cuss, slam doors in front of my son. Who will intern cry because of her being angry. 
Since I had my son I don't fight back with my mom. I don't yell back. I don't slam doors back. I talk calm, and tell her I expect her to talk calm to me as an adult.. which doesn't turn out well either. 
I'm planning on moving regardless within this year.. sometime. I'm just afraid of her lashing out because of it. 
Any tips? Advice? Anything.. literally anything will help. I'm feeling not as confident as a mother and as an adult that can make adult decisions because she is constantly in control of my life, and everyone else's. 
Thanks in advance, sorry for the ramble 😞