Am I taking things to the extremes by cutting off my family?

I'm 34 and just got married a few months ago and posted about this a bit before and got very good feedback. Except things have gotten from bad to worse. Exhausted, bullied, and just devastated. But I wanted to again share what's happened. I guess I just need some support-validation I don't know. But I'm sick to my stomach inside. I apologize if this is long. I moved to Texas a few years ago on my own. And that year my dad was diagnosed with Alzheimer's. I saw the signs and told my mom they weren't normal and to get him into a doctor. She did not. It was until about 6 months later that he saw a doctor.

In the past 6 months it go so bad he was put in a psyche unit and then a home, as my mom was not handling it well and was having a breakdown. My brother who lives close to my mom was at her beck and call. And when she needed him or needed me to fly there all the way from TX, we were expected to do it. And we did. And I was trying to do my best to make appointments for my mom, find my dad's home and visit about 4 times in 5 months. All while planning my wedding which my mom had no involvement in. To which she told me she didn't think she would attend. Nor my dad. Well she ended up attending. And my brother was angry because he was carrying a lot and felt she was too demanding-and I agreed.

Now in the past few years my brother and I have not gotten along. He has been very harsh when it came to my own recovery from depression (my own mental illness). He always thought it was fake, even when it became serious and I needed treatment. But recently we got a long. And he walked me down the aisle. And I was so happy I told everyone how happy I was my brother and I were getting close. He would call me to vent about mom and I would offer support. It felt good he would actually call me. Well my mom started making demands of me to fly there every weekend to help. And two weeks after the wedding, she told me she may take early retirement and move in with me. To which I told her, I didn't think it was a good idea right now. She is 63, healthy, has a job. She was just grieving and I would be there for her but can't have her live with me.

Then as we talked about her visiting me, she told me she would need money every month. Even though she has assets, money, a pension, six figure salary, and an inheritance. When I asked why (although my dad's treatment is crazy expensive) she couldn't give me a reason. Look, I don't even own a house. I paid for my entire wedding. I told her I can't and started crying from the pressure as I felt guilt. She said ok it's fine and let it go. But my brother didn't. When I told him my anxiety I never expected he would turn on me. But he did. He called me selfish and shameful. And told me to take a good look in the mirror when it came to my psychiatric state (because I said no to my mom). Later I told him that wasn't right and just ask he respect my decisions. Didn't hear back. I didn't hear for months until two days ago when I received a text from him accusing me of writing something on facebook that his girlfriend thought was directed at her.

I made a general statement without any mention of her, nothing. A sentence about passive aggressive people and that I don't like that. I like honesty. And she ran to him to blame me and he texted me threatening me to never write anything about them. When I told him that he's been so hurtful to me and I am his sister and why does he need to treat me this way, he ignored the question and went back to the accusations. IT was awful, and I literally felt sick all night. I felt bullied. I asked him to stop, he didn't until I finally said to him-do not ever text me again. I do not want any part of this drama. Not with you or your girlfriend. And, I felt angry. I was livid. And I eventually had a discussion with my mom and told her (when she defended my brother's actions) that she should have never made these requests of me, especially when they weren't ever needed and she is fine. She spends money, she has a house, she took my dad out of the home-she is ok. But my uncle attacks me saying I should live with her. My brother attacks me. And she does nothing to defend her daughter. When I told her she needs to take some responsibility for wedging herself in, her response to me was I don't really have time for this and hung up. And I didn't hear from her. So like an idiot, I text her saying it was unfair. And to stop hanging up on me I don't deserve it. I do everything I can to be there for her and have even said to come live near me. Or visit, we will spend time together. But nothing. She told me this is my fault and that I should have said yes to her and because I didn't, she will never as long as she lives come to me again for help. So it's eating at me. Because I don't think I did anything wrong. And therefore made the decision to cut things off for awhile. Cut them off. Is this too harsh?