Granite,
I'm sorry that your t canceling your appointment has set off your rejection and abandonment triggers. Does it bring to mind other times when you felt unimportant and forgotten?
I think Tree made a really good point, and that is that your t doesn't know you were working hard preparing for your session. She doesn't know anything about what you think or feel except what you've told her. When she canceled for the seminar and said she'd see you on your next appointment, that doesn't necessarily mean that she wouldn't see you sooner if you let her know you really needed to.
I understand that you feel angry, sad, and rejected. And i would feel very disappointed myself if my t canceled! But i don't see anything in this situation that indicates that she doesn't care about you and want to work with you anymore. In fact, when reading your post, i wondered if your t could be taking that seminar in order to help you in your therapy? We just don't know.
Has your t cancelled repeatedly or done other things that make you feel you cannot work with her? I hate to see you terminate now. You were doing such good work here on PC coming up with ideas on how to break through your silence and communicate with her. You could be on the verge of a breakthrough.
I'm sorry to hear that your pain was so bad that you self-injured. It sounds like you have alot of difficult feelings inside that you need help with. I'm glad you're feeling a bit better today.