In a somewhat random series of thoughts, seemingly unrelated at the time, I think I figured out where my anxiety comes from. Not sure what to do with it, but I think I get it.
Anxiety is worry and fear about things that haven't happened yet. For some people that's about the random things that could happen, and for others it's about the things on their plate that they need to do, like some work task, parenting action, or maybe even mundane things that they think they must do around the house. I know that a fair amount of mine used to be sourced from concern over a lot of things out of my control, like environmental issues, racism, fascism, you know, the big societal things. I've learned to manage a lot of that by agreeing to myself to acknowledge the things that I do about those things as adequate in scope. But for doing "stuff," that's where my anxiety is coming from.
It's hardly surprising that this is another symptom of midlife. Time, relative to my inevitable demise, is finite. That brings a certain sense of general urgency, to make the time "count." So when I'm idle, my feeling is that I'm not using that time adequately. I imagine this might even be one of the reasons that sleep is not as easy as it was for me.
The funny thing is that with age, I've also gained the wisdom to understand that life engagement is not a linear phenomenon. Throw in the variability of ADHD and ASD, and I know in certain terms that I can't be "on" at all times. All-of-the-things can cause fatigue, and it isn't just sleep that helps with that. Low engagement in the form of slacking, daydreaming, passively being entertained and such is OK as a means of recovery from the effort required to do life the rest of the time.
I don't know why this is so difficult to accept, because I know that I felt this way even 15 years ago, before middle-age. I know some of it is cultural, that American dream nonsense that we all should hustle to achieve some arbitrary definition of success. (Which, by the way, helps obscure the systemic issues that make it harder to get by for some people.) Some of it is certainly self-imposed as well, as I've always wondered if what I do has the scope to matter. As I said, I'm at peace with the limitations of that in a global scope, but it doesn't mean that I don't think about it in a more localized manner.
This is something that I have to work on. Younger me enjoyed passive entertainment, but now I have trouble committing to a two-hour movie without feeling like I could be doing something "more." It used to be easier to just be horizontal with headphones on and lose myself in that experience. I need to get back to that.