You deserve answers. Sudden termination without an explanation like that is unprofessional.

Your T has to be somewhere. Start with the office where you used to see her...and ask for information and/or a forwarding address. Google her name.

It would make a difference to me if she left due to a sudden illness, whether she was fired, or whatever.

I was terminated once because my Ts job changed. That was fourteen years ago and we remain in touch to this day....so don't give up...that's a possibility.

I'm glad you are thinking about engaging another T. The new T will be able to help you reach some kind of closure.

Whenever I am struck with grief, I eventually feel better once I take some kind of action.