I don't think you literally told her "I think you deserve to be dead" but it's pretty clear from how you are handling her right now you were cold and extremely insensitive when she was going through a really hard time.

She obviously has some really strong emotions going on, and I distinctly remember having this exact conversation before and her calming down once you stopped actively antagonizing her. If you can't handle it you really should just ignore her because it's doing neither of you any good to keep rehashing this.