Did you improve your mental health? I don't know, there are just too many variables in life. But I do think cutting off communication is an appropriate move. It's not ideal obviously, but if someone refuses to treat you with respect then I think being forward and honest like you have been is a fine way to deal with it, I may have done the same thing or something similar in your position.

Maybe she's holding a grudge, maybe it's something else, but until she turns around and forgives you/herself/moves on/whatever else, she will most likely be a strain on your life.

What do you think you'll do if your sister does get in touch?