Hey Mariposa,
I'm really sorry that your family situation is so hard. My family is dysfunctional af, and I had to cut ties with my father - it's been over a year since I've spoken to him. But the good thing is that once you make those really hard decisions, you can focus fully on your own healing and wellbeing.
You really are the most important person
My advice would be to focus on right now - what can you do to help yourself today, even for the next hour? Then, hopefully when you're feeling less overwhelmed you can take some time to work out a plan of how you will deal with the situation. Family stuff is so hard because you're technically supposed to love them no matter what. But at what cost to yourself?
Are you able to see a counselor or therapist? It always helps to get a third party view and can help you with processing everything.
Anyways, please keep posting/venting/etc. <3