I'm sorry that you have to deal with that person.
I am 57 years old. Over the years I have had to deal with people like that "crazy" women in your office. I used to cry, worry and moan over people like that.
I came to the conclusion that I wasn't put in this world to be abused. I just let them go on their way now. Those kind of people hate themselves and want to take it out on the weakest link in their sphere.
Pray for those who spitefully use you and do what you can to help those who need you. I don't worry about people like that anymore. Their day is coming.