Unhappiness from social media for me happens when social media makes me aware of things that make me unhappy. For example, I get a lot of news from Twitter, and sometimes the news makes me unhappy. I have a great diversity of friends and family on Facebook, and sometimes one will post something I find really distasteful.

If I was reading a novel instead of Twitter, I wouldn't experience that unhappiness.

The thing with social media is that the content is in such little morsels it's easy to say "just a few more," and the platforms are carefully designed to serve you the kind of content that will keep you saying that. So it's easy to "accidentally" spend way more time reading social media rather than (for example) reading a novel. That can tilt the balance toward more "makes me unhappy" content and less "makes me happy" content.

And sadly, the more tired I get, the easier it is make that sort of mistake--and also, the more that sort of unhappy stuff tends to affect me.