If I'm doing a lot of reading and research, anything short of mindless genre fiction is probably not going to work. When I'm just interviewing people and not exerting any real mental effort, I get itchy for more substantive works.
You've read enough books for a few lifetimes, as I recall, so I wouldn't worry too much about a bit of a regression towards the mean in your reading preferences. 
I work in a corporate residential treatment center for teens with emotional/behavioral/neurological disorders. Some days, I work 7-6, others I leave at 3, depending on what I have left to do and if I have the energy to continue doing it. Mostly enjoyable work (the students might disagree 
), but between that, working PRN on Saturdays and/or Sundays at my old job, and rehabbing a mild ankle sprain, I haven't had much time for what I enjoy most these days, running, much less leisure reading.
That might change soon, however. I am planning on going on vacation in two months for nearly a week.
Je suis méchant.
*NM*