She is displacing her issues onto you. Try to remember that when you read the emails (especially if they are accusatory) No one can make another person feel anything (she is choosing to feel this way)
You can still acknowledge how she feels and then perhaps say something like " I hope that you will take care of yourself; it sounds like you're hurting." Let her own her problems and you do not have to lower yourself to her level at all. This is what she feels and unfortunately she's being inappropriate about the way she verbalizes her feelings and needs. It is fair for you to let her know that you would not be able to continue to receive this sort of correspondence since, it is unhealthy for both of you.