Sounds completely normal to me. I've done almost the exact same things in my therapy. The pain you feel is unbearable, the needing and the pain of that and rejection.

Of course you need to tell T exactly how you feel how even her using the same excuse feels like she maybe bluffing Why she had to cancel. But what I discovered was T couldn't never not let me down at some point or other but it's in how it's handled. I was let down as a baby so dramatically that there was no learning about let downs in a normal gradual way for me, it just ripped me apart. But each time I felt let down and talked about it eventually with T I learnt to tolerate the pain. I grew to experience that being let down is normal and tolerate that. We have to experience that wound but with a different outcome. A better handling. It still difficult for me but I don't fall apart, I don't act it out am able to talk it out and process it without getting stuck.