I have that happen too Jane. It can trigger the PTSD when things are sudden surprises or change the way you are describing. It was good that your T talked you through it and is helping you calm down. I have found that because of the trigger, the part of the brain we use to regulate and monitor the rest of the brain, the frontal part, the conscious mind, gets disturbed and you are right, it is hard to concentrate and process.

Yes, you are right, you already struggled with being anxious and working on self soothing and making decisions on how you will proceed with the challenge you were faced with. It is understandable that when you were faced with these "changes" so last minute that you would struggle. It's ok to talk about that and work through it so your mind can slowly learn how to address things that are unexpected like this. You are going to need to step back, self sooth and calm first then "slowly" think about how you will work through this new challenge. I know that is not easy Jane, each time this kind of challenge happens, can only be handled by "slowly" developing new skills where you relearn how to self sooth, and calm down the "alarm" you are experiencing. You did the right thing by reaching out and talking about it to people who are understanding and supportive with you.

(((Hugs)))
OE