Ask HN: Anyone else get depressed when you're not actively digging into a topic?

Sometimes I'll be "done" exploring a topic/project, but haven't yet found another one to dig into (or just run into some sort of a break/gap in mental activity), and I'll basically get depressed (not technically, just temporary low mood) without having something keeping my brain engaged.

I wonder if any of you have advice on managing these gaps. Or maybe strategies you've adopted to always have something keeping you engaged?