I need to vent 😞

I have nowhere else to put my feelings out there but here. My mother for the past year and a half has completely changed. She will pick fights over the stupidest thing and if you don't agree with her you are disrespectful and she disowns you. This has happened 6 times during this period at least where a simple conversation where she brings up something, or bringing up something stupid has turned into me literally having to stop talking to her because she can't let it go she will keep going until you're crazy stressed out. One of the first few times was because my older brother was going through custody for his son and we got on the conversation of my nephews mother because she was having visitation for him. I told her I think it would be good for my nephew to have both parents IF she was being serious about wanting to be in his life. She completely flipped out because she disagrees about her seeing him. It was very shocking I remember because she was never like that before. I tried to let it go. Then after that was another incident where she doesn't like my little brothers girlfriend. We will call my brother dean, and his girlfriend shay. Well shay posted a picture on facebook of her standing next to another boy. My mom flipped out AGAIN saying shay was disrespecting my brother and that when they're in a relationship they should have no friends but each other. She casually asked if I saw the picture and I said yeah. She asked if I thought something was wrong with it and I said no not at all. I was very confused by this because it seemed innocent. She literally disowned me and my little brother because we didn't see anything wrong with it and pulled the "being disrespectful card" I stopped talking to her because she said loads more that were hurtful. So I go through this cycle where she starts an argument and goes crazy and I have to block her because I can't deal with the level she gets to. When I try to diffuse the conversation she keeps going like she almost enjoys it. So I stop talking to her until I feel guilty and talk back up slowly. Things go good until some random thing makes her mad. One time wa shecause my son was over a year old and still nursing and she said she had a right to say when he stops because she's his grandma. Another time was at his first birthday when she was suppose to drive to his party (14 hour drive trip) it was planned for months. The night they were suppose to leave I couldn't get a hold of her. Turns out my mom and her husband (one of many she's had) got into an argument about emails from women. She met this man on Craigslist for a sex ad. I don't know why she bought it was going to be a faithful relationship. Meanwhile she's cheated on every man but one that I've had in my life. So she went on about what she should do because he was being mean to her and didn't know what to do. I said she should leave him but she didn't like that answer I guess and flipped it on me about how I moved away from my family and how my boyfriends family isn't as important as mine and guilting me. Stopped talking to her again. Another time I can't remember what caused the argument but it was really traumatizing because she was telling me she was going to kill herself and it was going to be my fault. It was way worse than just that but I couldn't take it anymore it was horrible for her to say that when I didn't do anything bad to her. I stopped talking to her and told her she needs to get help. I was told her therapist says I'm the wrong one including my brother and she's right. It just keeps happening like this and the guilt kills me. This recent argument was probably one of the stupidest ones. It was about a man who my little brothers grandma was married to when we were little and my mom tagged us in some song on facebook and said "remember when chuck would sing this" or something like that. So a family member of my little brothers dads family commented asking if something happened to chuck. I mean he'd be very old (including the women who commented) now so I completely understood what she was asking but my mom took it badly and started trying to pick a fight with the lady. I told her I saw it as genuine curiosity if something happened and she brought up everything bad hat has happened to us as kids trying to convince me that my little brothers dads family is evil and horrible and how my little brothers dad is horrible. Now I can't say he wasn't. He abused my older brother and we went through a lot. She kept bringing up every incident that I had almost repressed in my mind and forgotten about. I am also pregnant and the memories gave me an anxiety attack because every time I said I didn't want to hear about those memories or for her to stop she wouldn't and it was like a volcano rising and I couldnt take it. I told her she was no saint and if she had not put men first in our lives then stuff wouldn't have happened. But she thinks what she did wasn't anything bad. She then says how her therapist says she has ptsd from my little brothers dad. I said if you have ptsd how do you think we feel as children watching that. You were the adults who could change the situation not us. She kept going like guilting me like it was all my fault but we were kids!! I still talk to my little brothers dad. I believe they had a very toxic relationship and that brings out the worst in people. I had an ex and the actions I did while dating him I could never imagine now. She gets mad that I talk to him but she doesn't get it that he is my only father figure and that's stretching it. My father when I was 7 months old tried to kill me. He signed over his rights and I was told my little brothers dad was my father until they divorced when I was 11 and obviously my little brother was the only one he was seeing and I was told why. He had no rights to me as much as he wanted to see me. I remember my mom telling me he was yelling about how he wanted visitation to see me but he legally couldn't. So I try to hold onto that because my real father who I met at 15 with my own doing and scheduling is not a father to me. There is no relationship like a father daughter with him. It's like an acquaintance. She has tried having me call the past three men she's married "dad" and I can't even stand father figures now. She will never comprehend why I'm upset it's like it goes over her head in one ear and out the other. I'll send a huge paragraph calmly explaining the past incidents and how she starts them and expressing my feelings and she literally just said "why are you bringing up shay that is already done the kid was gay and he's been over my house" like no that isn't the point of me bringing it up. It's the fact that you disowned your kids over it. So now she sent money for my son for Christmas right before we stopped talking and just sent money for his birthday. So now I get a text from my stepdad asking when they can see my son. I am so upset. I am not even talking to my mother how could they even think they can come stay and see him? I feel like that was their intention with sending money was to ask that. I'm so paranoid they're going to pull some grandparents rights thing because my mom mentioned it before when my older brother wasn't talking to her with my nephew. I have this fear she's going to drive 14 hours without me knowing and just show up and I actually fear it. The night she was threatening to kill herself I made it known to family that she needed help and sent them the messages and I was so scared she was going to drive to my house and kill me. I hate this. I just blocked my stepdad from texting because I'm still not over this at all. I'm sorry I just needed to vent. Sorry if there are horrible typos.