It may be her transitioning to retirement, she may just be slowing down a bit - something may have changed for her since having the conversation with you. Or she may just like the idea of working a bit less but all of that is her business and I'm not sure she owes her clients an explanation. She hasn't said she's going to stop working all together - it may be worth talking to her about your fears about your therapy but don't be surprised if she doesn't tell you much more than she has already.

Have you been with her forong? I'd hope she would be more open with you if you've been a long term client.