I'm really sorry that T is no longer meeting your need for a therapist.

It is thoughtful of you to consider her potential loneliness. But what about your need for therapy? Is it hard for you to see your needs as being just as important than as those of others?

If you need therapy, I would suggest that you find a true therapist.

If she becomes lonely through the loss of a client, she can address that issue. It does not have to be your responsibility. Do you tend to make things your responsibility more than maybe you really should?

Here is a thought experiment. One idea would be to go visit her once in a while as a friend (without paying). If you had a different T, would you want to do that?

If yes: then you can get therapy and still help her out.

If no: well then perhaps you should not deny yourself therapy for her sake.