I would keep reminding myself that because I am doing well does not mean I am near termination? So you got straight A's in 9th grade, you aren't out of high school yet! Another thing I would want to learn is to see my T as my partner in therapy and good partners don't just make unilateral decisions, your T is not just going to terminate you, rub her hands together and say, "Well, that's that, I finally got rid of that Ambra!"

It sounds like you have a lot going on in your head that you need to work with mastering before you need to worry about what your T is going to do? If you stay on what is affecting you and what you need to do instead of imagining things about your T (since you aren't her and haven't asked her and it is not what
you have been working on for your therapy) it can be a little easier. There is scary enough stuff happening like this new thing with your boss.
I would definitely tell T you are struggling with both fear of termination because you are doing well issues and the problem with your boss. You say the problem is okay now; definitely tell her how that happened, that it became okay. When a boss humiliated me in public I was near tears then got angry and came up with a plan so it would not happen again and empowered myself and it was one of the best stories I had to tell my T that week, it felt so good that I was actually using what I was learning in real-world situations outside therapy.