If you can stand one more session with her, ask her, directly, this very question.
And, if you truly cannot settle into being with her, then tell her, directly, why you are choosing this option.
That is your complete right and I would not change it in any way.
If she did have this reaction, (and it’s truly helpful that you copped to others having a similar reaction), it could be you’re on the right track to finding a solution to what has been bothering you.
If perseverance is the path, then persist and take action on your own behalf.
You may have uncovered something very important in the first session.