I realize that coming from someone with BPD, to someone with BPD, this is a little ironic, but I'm going to say it anyway

Remember that your T is human too. There is an excellent chance that she got caught up in her own life and didn't realize how much canceling the appointment would affect you. She may have seen your e-mail and realized how important it was for your treatment and been genuinely concerned. I don't think that a 5 page e-mail would cause a T to terminate your relationship...

I hope the session goes well. I know what it feels like to fear pushing people over the edge, and what it's like to push people away even though I don't want to. Apparently it's what we do.