When you mentioned your pdoc does a bit of therapy, I thought of mine, too, for the same sort of reason: he helps me see what my therapist is likely doing to help me...he'll let me talk to him about my therapist, and will refrain from second-guessing him.
So, I like that idea a lot.
I am glad for the information about the size of the class (size really does matter....such a tired joke....) Because the class is fairly small, it is more of an issue than a lecture-size class. Still, 20 will give you some anonymity. With that small of a class, the dynamics of the class will act to sweep you up in a flow that will diminish some of your concern about the relationship with your therapist...It'll have a pace that sweeps you all into it.
And I agree with other posters--that your therapist will be focused on attending to his own role as prof and to his responsibilities to the class as a whole. In any individual work, he'll be careful of the relationship. You terminated with him a week ago, right? So there will be a little time before the term starts? And a little time to fill in the time opened up by ending therapy...maybe that will help some, too? This situation, I know--I am absolutely certain of it--would send me into a panic, too...But I also think my panic would last about three days...then I'd start to be more of a problem-solver about it. Maybe you'll have that lucky grace, too...I hope the worry will become more manageable...I am so sorry this is so upsetting now.