I think I understand what you're going through. Me too, I find it easier when my T is at work, although I absolutely want her to enjoy her time away from work too. But it's difficult.

Could you try to come up with a challenge for yourself? Something to tell your T about when the vacation is over and something that can keep you busy... now that you have so much time on your hands?
I often start a 'project' when I have too much time and just know that I'll start to feel bad, miss my T, will start worrying, etc.
It can be something creative, something you've been wanting to do for a long time,...

Sometimes for me it also helps to start writing. Sometimes every day. Then maybe in the end I will send my writings to T, sometimes not. But a reflecting a bit can be helpful. Unless it makes you more sad of course...