Do you think the feeling is transference and that you are missing feeling good about someone in your life? That it's not about your T at all? I can relate because I used to always want more from my other Ts. Maybe it's something lacking in YOUR life, and not something your T can give you.

Can you bring this up with your T? Have you always felt this way about her or about other people? Wanting more? Is the empty feeling something new or has it always been with you?

You said you feel empty when thinking about her. I get it when you say it could be because you're not part of her life. That could make you sad. It's made me sad to know that my T and I can't be friends even though we get along so well. I like her better than most of my friends.

Is there something your T could do so you'd feel differently? A while back, you were going to ask her questions about herself. Did you ever do it? Maybe she seems like a stranger because you don't know much about her.

I hope you can pinpoint what the problem is.