Sadly, my ex-best friend, who was like a sister to me, has been battling a terrible bout of depression on and off for years. She lashed out abusively at me recently for refusing to play along in a game of self-victimization and I called her on the behaviour. For our past three conversations, she absolutely refuses to admit that she has caused me harm and has the audacity to try and reverse the blame on to my shoulders, as if I caused her to behave badly. She even went past belittling my pain and tried to gaslight me into believing a outrageous made-up reality. I understand that she's really struggling, but I would have put it behind me if she could simply say "I'm sorry I hurt you" and actually mean it. Since she can't do that, I'm calling it quits on the friendship. It's truly heart breaking.