Sounds like you might be doing some understandable flailing in anger and anxiety because you're still adjusting to the transition between therapists. What do you think?

It's hard to trust her, I imagine, but I don't see an objective reason to fret that she will not show for the appointment- was she not feeling well last time, or something?

Can you give yourself some reassurance that you will be okay, no need to push, just do something comforting for a while and see how the day goes?

Alternatively, if you're feeling more mad than insecure, maybe time to have a good tear! Go beat up some cardboard boxes or write an I hate you letter, haha.