It might be because of the medications. Hormones any number of things. Just be supportive for her. My wife can deal with these issues to, and it's frustrating for me to consciously realize that she is having to be the stronger of the two of us and that will kind of in a way trigger not really depression, but more of a guilty feeling. But I am not a doctor by far, and every person is different, could be some hypo. Does she have a therapist that she can confide in that she trusts a lot?