Thank you for the responses.
I described my problem to a very trusted friend (and fellow developer). He almost immediately said "burnout".
This doesn't feel like the last time I was burnt out - that was very intense. This feels more "low level". Of course, back then I didn't really have the opportunity for a break. Whereas now I do.
It seems that the bulk of advice coming in is to take a break. That was also what my friend said. And so that's what I'll do. On that note, I have an additional question: How long should I take a break for? How do you tell when to stop?
To those suggesting that I might not truly enjoy programming (and/or game development, etc): I considered this possibility very carefully. Particularly because I'm biased by some rather large "
sunk costs". I'm pretty sure I still love it. My last non-uni programming effort was about a month and a half ago and had a great time. But then "finishing uni" is a fairly significant upheaval in the mean time.