My T was away for 9 weeks this summer when I'd just started seeing him - that's his normal summer holiday, apparently. I found it pretty tough going, actually, especially since I had no other emotional support in RL over the summer. Somebody on here gave me the advice to try to think in one-week chunks, focusing on the next time when I would have had an appointment, rather than on all the future missing appointments at once. I journalled a lot as well.

I'm sorry your T is going to be away so long. I hope he can arrange for some kind of support while he's gone.