The thing about spending a chunk of time when you're in pain or on narcotics or under assault from chemotherapy drugs is that it's not very conducive to being productive. With the singular exception of the sorts of projects that lend themselves to being worked on in brief spurts of activity, the results of which can be espressed, when you feel yourself starting to fade, in a few brief sentences. Or better still, by filling in a few fields in a flat-file database1 or even a spreadsheet.
Excellent as this may be as a way to make use of one's cogent hours in such an otherwise unproductive time, there is a downside, I have just realized, in that if it goes on long enough — a couple months, say — these projects tend to accumulate.2 And one of the things one is especially ill-suited to in such times is prioritization As witness the fact that I am presently (2016-02-03T01:01) writing this, rather than working on the chronology of recent events I owe my primary care doctor. Or, probably an even better use of the present moment, sleeping.
1 A moment of silence here for those of you old enough to remember the late lamented pre-"Pro" FileMaker, or even the database module of MacOS 9 AppleWorks. Sniff.
2 As, for instance, footnote 1 reminded me that I've been meaning for some time to look into whether the database module in Libreoffice might be usable as a not terrible replacement for old-school FileMaker.