Along with the suggestions here can also recommend a short hike. There’s also a bunch of short, fulfilling games on itch.io and the developers see more of your cash vs steam, worth considering if you’re so inclined.

I also go through phases like this, particularly in the winter. You could be suffering from depression or if this is a more recent thing as the days get shorter maybe its SAD. Get some sunshine and a SAD lamp and see if that helps. If not, worth talking to a professional like others have suggested. Godspeed fellow gamer!