Ugh. When I find out, I will let you know, lol!
I went through a horrible time with my mil. Really, it's still going on but I haven't seen her in a couple yrs and haven't directly talked to her in about a yr. My H still talks to her about twice a month. We still hear of her lies and schemes from other people.
Before the complete break down, she was passive aggressive city. But I only saw her for 2-3 times a yr. I could not have stood it if I lived closer.
As it was, I did a lot of exercising. I talked to my best friend. I went on high blood pressure meds for about a yr. dealing with it. Don't let it get to that point. Physical separation is the only cure I know of. That said, everyday, just about, I pick up that burden again. And everyday, I lay it back down by prayer and busyness. Find other, less manipulative people to be around.
Also realizing that it's their problem, not something you've asked for, helps.
Boundaries are there for your protection and emotional health, not as a punishment for that manipulative person. What I am saying is, don't feel bad for setting boundaries. It's just as good a healthy move as exercise or eating right. You pick and choose the food that goes into your body. You have boundaries for bad food because of the effect on you. You are not punishing the bad food! You just know its not good for you. Part of your stewing about this person is because you don't have a plan for keeping her from hurting you again and again. Make a plan. Anxiety will decrease as you DO something. Good luck!