My T was older than I am (and I'm 61 now) so too old for maternity leave but she was from another country and use to go there every winter, sometimes for the equivalent of 10 weeks.

I worked on therapy "alone" while she was away; wrote weekly "diaries"/progress reports and mailed them the end of each week, to her office. I thought up various other projects like numbering all the days (1-70 in your case) and writing the "best" thing I learned that day or that happened to me or something of that nature. I like a certain degree of difficulty so had another time when I had to write only one sentence to describe the entire day :-) I tried to use the time to "practice" what I had been learning in therapy or to try things that I could not do if my therapist was there. I almost always made sure I took my vacations when she took hers, too, so that would take up some of the time.