Getting referred to a new T *is* really hard... you're not a baby! It's hard to feel like you've found someone you can work with, and to commit to that, and then have them decide that it's not going to work out. (It's awful!)

It sounds like she is going to help with the transition? Does she know the new T?

Hang in there... hopefully the new T is someone who you'll like, and who will be around for a long time for you!