I am responding to you because you mentioned this could be related to therapist but because you did not say what happened it is hard to speculate.
For me, at the beginning of my therapy (during to get to know you phase), I would occasionally (seemed often but looking back was occasionally), find myself gripped by unbelievable anxiety and even some insomia ...so high, I honestly thought I'd lose my mind. It DID relate to my therapy...cause they were poking or I was poking the bubble of memories I shut down from years and years ago.
These are few things that I did, remembered or worked for me in random ways. Hope you find some help in it.
First each high anxiety was a building up of breakthrough...cause when it broke, I was like wow!!!!!!! it was worth it...a great insights came apart.
I realized also this was my child part pushing me to understand something about myself (I have a lot of body memory because bulk of my trauma started before 4yrs and just got worse over time) so my inner child power was pushing through for something. I asked one time, what do you want? and kept answering until the right answer came --- that time, the answer was I felt threatened! I was scared of the therapist and honestly, I was so relieved...cause this revelation broke the trance of anxiety and brought me to here and now. I learned as I started to wake up from the anxiety grip, that my therapist at the time had aggression counter-transference. basically she was encouraging my aggression (my mom side that is my shadow) and few months after that breakthrough I left that therapist.
I wrote stories with my non-dominant hand, and weird but great things came out.
I put intention before sleep. I love to solve my anxiety while you sleep. dreams (IMHO) are sometimes the key to healing childhood trauma that has no language but symbolism and feelings -even a nightmare dream is useful for me. I actually always always push things to my dreams because my brain and my body know way more than I know about my past.
I bring up in therapy and ask the therapist, if I can sit on it...I do not have to talk but feel the anxiety in the room with them...some therapist may not like this and fidget or ask questions but that also tells you something concrete about the therapist.
The mere fact this anxiety is so gripping and arose from the therapy means you are very close to open a chapter and find a real answer.
Hope this makes sense