I do similar things. After the first session with my new T, I was a hot mess, and it took me a whole week to be able to figure out that I misinterpreted her actions and words based on past experiences...
I find it really difficult to speak when I'm anxious, but I tend to write easier. Most of it is just rambling journaling, but I eventually get to what it is that is freaking me out... Does anything like that work for you? Or maybe art to help get the bulk of the emotion out so you can face the other stuff in a more balanced way?