(((((((((((BlackCanary)))))))))))))

There is SO much in your post above to bring to T. It's okay to be angry - really and truly! Can you tell him how you feel - that it was so sudden, that it feels like he's trying to get away from you, etc.? It feels like that is all SO important.

T and I change where we sit a lot, but I get to be in charge of the seating, so it feels safe and empowering to me. If I walked in there and T said, without any warning, from now on, I'm sitting here and you're sitting there, and that's that, it would feel REALLY confusing and invalidating and probably scary. I'm sorry that happened with your T

I know it might feel tempting to start looking for another therapist, but I hope you'll at least go and hash this out with him first. Maybe you'll come to a resolution you can both feel happy with.