I have problems like this too, suddenly becoming suspicious of why my T asked me a question or worried that his family is socializing with my sibling's family etc. It is an issue of trust and not the greatest attachment skills stemming from trauma history. I used to react to these feelings strongly, but over time I have learned to observe them and be either curious about them, or let them go like as if they were a river. That feeling of paranoia is so persuasive and poisons the day. Sorry you are struggling with it. I would hate the situation you describe, and unless they are both ultra-professional, they might talk about you. Hopefully they do it with affection. You could tell your new T the deal, and stress you want your confidential repeated so you can trust? You could greet your old T, say hello etc so it lessens the flinch factor?