My T's vacations bring up all sorts of things for me, about self-reliance vs. depending on others, asking for things I need, the place of therapy in my weekly schedule, feeling abandoned, tolerating distress. If that's not therapy, then I don't know what is.

My T usually lets me know about her vacations maybe 6-8 weeks in advance, and we talk about them (usually on and off) as often as I want to.

I find it helpful that I can have strong reactions to her absences without her seeming to feel guilty or weird about leaving. Maybe your T hasn't mastered that yet, so she would rather not talk about it?