Yeah it's a really good tell. If you can't find the energy to play your favorite games, it's probably a sign you're not at a good baseline state. Depression makes normal activities that are usually really fun, not fun at all. It can be anything you like to do really, but I have a feeling if you subscribe to /r/factorio, then not finding factorio fun probably means you're depressed. I mean it doesn't have to be blissful, but if you aren't enjoying it or any other video game, then it's something to pay attention to.

I usually try to force myself to exercise if I get too bad and it kind of resets me, but if you're very depressed then it's hard as fuck to "force yourself" to do anything that's good for you. Sometimes you just have to ride it out and wait for an opportunity where you feel you have the energy to do something about it and strike then, like riding out the flu.