Thank you all. Long story short, I did decide to state a break a couple of days ago, before I had read these responses. For various reasons it seemed like the right thing to do. Now I don’t know. There was immediate nasty pushback but none since. But I am finding myself anxiety-ridden about when to reconnect, having made a bad decision, etc. I’m trying to talk myself through it, ie that I’m going my best in a hard situation. And I’m trying breathing and other calming techniques. Not working great. Wish I could just be asleep!!
Don't beat yourself up because of the nasty pushback. Remember that she is disordered, so trying different strategies to see what could work makes some sense. It's like a new parent that has to try different strategies with their little one in "terrible two's" to figure out what works for them and the child. You're just trying things. It's ok. Don't beat yourself up for it, and there is no "wrong" decision. Just different things to try. It's early still, and time will tell how well/poorly this worked out. Then you can note it, and put it in the memory bank either way. Bottom line is you are doing your best in a difficult situation and learning how best to take care of yourself.

Have you tried splashing your face with cold water? That actually didn't work for me, so I filled the bathroom sink with cold water, took a big breath, and plunged my face in it for as long as I could stand it. Remarkably, this worked quite well. It kind of shocks your body to reconnect with the mind, and get out of your own head.
Another thing that works for me is physical activity - moderate to intense, or a long walk in nature (an old growth forest trail works miracles for me) or a walk on a tidal beach (it's the repetitive sound of the surf that does magic for the nervous system).
Hang in there WMP, these feelings will settle. Just keep taking care of yourself, because that is what is needed for them to settle.
As for being anxiety ridden about when to connect. You are focussing on the future. Is that really helping you right now? Ruminating about stuff from the past on what got you here isn't going to help either. Focus instead on just the present - what you are doing to take care of yourself now, and your daily life.
With help from my T's, I learned with time and practice that the time for me to reconnect was when I was feeling better (safe and back at baseline). Reconnecting when we are stressed, or still resentful, angry, hurt or otherwise distressed, isn't the time. Feel better first. Does that make sense and seem reasonable?