I can't speak for your therapist and am certainly not trying to defend her... but it's obvious that you cared for her, so it might be less painful to look at the possible flipside situation...

If she said she wanted to cut her caseload, didn't want to be on call, etc... it's possible that she was extremely overwhelmed and nearing burn out. If that is the case... then her nerves were likely fried... and like she said in her message, she blew the response to you...

If you two have been together awhile, it's an ending for her as well, and sometimes, those don't come easily... and emotions get twisted. Despite being a sad panda right now, I tend to be pretty optimistic (probably overly so) and I'd like to imagine that your therapist just was processing so many of her own emotions about being burnt out and trying to lighten her load... that she wasn't able to appreciate the consequences of her tone.

It's just me, and I know others will disagree, but I'd give her another chance... it might be the peaceful transition you need to take the responsibility off of your shoulders. Of course, she could hurt you again... but I'd say if she was a good therapist for every single day until the last one... chances are better than not that she will try to offer you a better explanation. goodluck!