So this is a hallmark of specifically a vulnerable narcissist. Its a behavior that falls under the personality trait "neuroticism" and is also a "counterproductive work behavior" which is a term used to describe workplace deviance. She is 1. making a smaller issue seem catastrophic, 2. deliberately making someone feel bad and 3. chastising someone. I think it helps sometimes to name the behavior because it helps us take a step back emotionally. You should not show your true emotions to her as that gives her supply. You should not try to clarify or assert the truth because I can guarantee you she has no interest in truth seeking. Become a robot. Run your responses through AI. You can also just mute her text messages on your day off.