Adam, my pet off-work project is also computer related. For reasons too long to delve into at the moment, I am a hobbyist writer of fantasy and science fiction.
Since I work for the US Government by day writing program documents and work on my own at night writing fiction, I don't have to be retrained during the transitions.
Serioiusly, I understand. You want to do something that either quiets your mind or lets it fly elsewhere. I've been doing this since the mid-1980s. I've got five full-length fantasy novels ready to go (but sadly, no buyers yet...) and two sci-fi novels in work.
Unfortunately, I can't tell you HOW to find the activity that you need. I absolutely understand - and agree with - the need to tend to your mental health, though. Good luck, my friend, at finding your own path to Nirvana.