My T studied burn out for her PhD and has very firm boundaries around email and outside contact. On days she doesn't work (weekend or vacation) she doesn't respond to emails at all. She prefers not to receive any, but if she does she will only read and respond on her next working day. On days she does work she only responds to email in office hours. She told me this at the beginning and has always adhered firmly to those boundaries. If people have emergencies outside those hours they are to call a hotline or go to the emergency room.
My T says those are the boundaries she has set for herself in order to maintain her quilibrium for work. If anyone needs a higher level of involvement they may prefer to find a therapist who is able to offer them what they require.

I didn't like that policy at first but I have come to appreciate it. The times I wish I could contact her outside of hours I just know I can't... so I find another way to deal. I actually find it much easier than the uncertainty and anxiety of not knowing if she will or won't read or respond to email.
On the flip side she holds up her end of the deal very well too. She is the most reliable and consistent T I have ever worked with. The few times she has had to cancel because of illness she arranged a different time for me to see her that week. She never takes leave without giving several months notice. And she remembers everything. Every single little thing.

For you I can understand it is more painful to have something and then have it taken away. But I think its important to respect your Ts boundary and private time since she has asked for it. It won't be personal, just your t saying I am on vacation and not really available, just wait til I get back.