I am very sorry with what you're going through right now. I may not know exactly how you feel, but I can definitely relate. I am having a similar issue with my brother. It isn't as intense as what you're going through, but if he cares about me he is not very good at showing it. I bend over backwards for him and never get that in return. The last straw for me was a week ago when I was having to go to the hospital for a procedure and was going to be given anesthesia for the first time. I was freaking out about it, and I had to have someone come and take me since I couldn't drive after and he couldn't even come and get me to the procedure on time. I was already a wreck.

Anyways, not trying to make this about me just wanted to give you a glimpse into my own relationship with my sibling and how I really can relate. Family is very important, but sometimes there comes a time with certain family members said where you just can't put up with them anymore, and I understand completely. Maybe one day down the road you two can work things out, but it seems like right now you need support and she's not providing that. Perhaps one day if both willing you two could try therapy together. I hope things get better for you soon.