PTSD, it is so hard when Ts go away and the whole routine is disrupted- I really feel for you! I think in some ways it can feel especially hard for those of us who have frequent out-of-session contact, because a week or two isn't one or two missed sessions, it's 7/14 missed days of contact with T! How nice that you're still able to text when your Ts away- from her messages it sounds like she will come back renewed and with lots of energy for working with you
As for suggestions, my strategies are similar to Tree's. I suddenly become an expert at fractions- counting down the time in 'two fifths... one quarter... one third... one half' gone. This works especially well the first few days as often each day will be a significant fraction of time down! It's less effective once you get stuck in the second part of the count down, which feels significantly less satisfying!
T and I usually have contact at the end of each day, so I have also in the past written a 'bumper email' to her and saved it as a draft. I write what I would have written if we had been texting as usual, plus letting myself tell her how much I miss her, my fraction games... anything I want to say.
I hope time goes quickly for you. When is she back?