Since early December 2018 I’ve tracked my mood and energy while working at the computer. This has been quite interesting in terms of self-reflection and adjusting both my work and personal habits. Maybe I’ll share some insights in the future.
Meanwhile, if you’re interested in doing the same, here’s the hacky way I do it. This is macOS specific, so I can’t speak to using Windows or Linux to do the same, but I suspect it would be similar enough that you can figure it out if you really want to do it.