I have that nasty pit in my stomach feeling when I speak to my addict brother too, which is why I very rarely speak to him anymore. It makes me especially sad since I lost my closest sister six years ago. And I have one other sibling but she lives far away, so essentially I am sibling-less.
It breaks my heart to know my brother is so alone but I truly can not have that negativity in my life. Mine was a choice of survival. I could either let go of the things that were pulling me down, or go down myself.
As far as your sister's recovery goes, she still sounds like she's got quite a bit of work to do. There's a chance that eventually she will come around and realize she can't treat you the way she does. In the meantime, you have a right to a life free of toxic behavior, no matter who the person is behaving that way!