Coming from a workplace where I had to deal with the odd bully and manager beginning to lose their marbles, it is best to get into HR first. There is a real risk of making the situation worse and you looking like the bad person if you confront her and she takes offence. Even the most diplomatic comment can be twisted by someone who is not in a sensible frame of mind and going by her comments she does not appear to be sensible at the moment. If you do want to deal with her first, do so with a witness in case it goes the wrong way.