I'm so sorry, am in the same situation and had a very difficult session 3 days ago. My T has always spared me the details so far, I've never been ready for that and am slowly disclosing some things here and there when I have doubts or something comes up and I have the urge to tell her. Disclosing at once in details is not for me.

Try not to hurt yourself..
apart from dissociation, can you talk to your therapist about how difficult it is for you to have to tell everything? And maybe having an "easier" session where you can talk mostly about something else or anyway leave the csa details part to the next time might help?
Maybe try to give her some hint, she might not know what your own pace is and thinks you are ready.
Wishing you well.