Struggling today

The TL; DR version of my situation: I moved cross country to help out my elderly mother after the suicide death of my father. She has always been a narcissistic and very immature, and this has only gotten worse as she's gotten older., especially related to dividing her children. I was a fool to pick up my life and do this for her, as I'm clearly the black sheep/scapegoat. She was "oh so grateful" at first. What I did not know was how she was badmouthing me behind my back while using me for caretaking, chauffeuring etc.
One day she randomly turned on me and began insulting me, e.g., "I gave you the best of everything--private schools etc.--and you have done NOTHING with it!!!" Mind you, at this stage, I had a great career and was entirely self-sufficient. I did not, however, marry some well-off guy and make babies and make her look good like her "my son is an ATTORNEY!" golden.
Note--when I met a woman in her retirement community with whom she regularly dined--the woman looked completely dumbfounded and said "What? I have never even heard about you." Huh.
Anyway...I honestly don't know what she did or said to get everyone against me, but she had me disinvited from my niece's wedding...and I just found out niece just had a baby--something I kind of assumed would happen soon but it's hit me hard being cast out.
On a slightly brighter note, another niece reached out to me recently very kindly and saying she wanted to connect. I've responded and we haven't set anything up yet but...
Anyway, politics does play a role. My brother and his wife are very wealthy Republicans and definitely have supported Trump in the past. I don't know about now and don't really want to. Other niece is definitely liberal.