I am learning not to punish myself for doing work.
Because my brain is capable of (seemingly) rational thought, I often have to remind myself that most of what my body (including my brain, which is a part of my body) does is outside my ability to control. I don't control the beat of my heart or the release of digestive enzymes.
There are things I can control, kind of: I can consciously take control of my breath, but most of the time, breathing happens without my input. And if I try to do things that my body really doesn't want to happen—like not breathing for long enough periods of my time—my brain will step in and say, nope. Not happening.
Then there are things that it looks like I can control: things like what I do with my time, for instance. These are the things where people talk about willpower and mind over matter. Areas where you have ultimate control. Maybe.
After years of trying to exert willpower, I have learned that, at least for me, certain things are much more like breathing than I imagined. If I do things that result in conditions that feel like punishment for long enough, my brain will step in and say, nope. We're done with that. Not happening. That's bad.
As an example: about eleven or twelve years ago, I discovered that even though I wrote fairly slowly (from some people's points of view), I can edit quite quickly. Or, rather: it was possible to cram all the hours of editing into as few days as possible. All I had to do was spend eighteen hours a day, vaguely pausing to have food arrive, eating at my desk, and pushing as hard as I could for weeks on end, after which I would collapse in a heap of unfinished laundry, having not seen the sun or experienced movement of any muscles except my fingers for the duration.
It turns out—and this should not have been such a surprise to me—that my brain interpreted me putting myself into forced labor solitary confinement for five weeks as a form of punishment, and since punishment is bad, it figured out that if I just didn't write books at all, then I would never be forced to do solitary labor again.
It turns out that my brain does not like having an abusive job, even if I am the one doing the abuse.
Writing in the aftermath of this is the same process as before, except it is different. For a while, I kept telling myself that my goal was to fix my brain so I could write fast (such as it ever was) again. I have realized that this is also wrong. My goal is not to get to the point where I can eventually speed up again. My goal is to be able to keep doing this, a thing I have learned from some very harsh lessons.
I have a choice between slow and enjoyable or not at all.
I am currently in the editing phases of a book, and I am trying very, very hard to be reasonable. To not set expectations and deadlines that will break my brain again, not because breaking my brain makes me write slowly and then I am not as productive, but because I should not break my brain at all, for any reason.
And so most of all, I am trying to enjoy the process, rather than trying to rush through it with the speed and ferocity of a cheetah running down a gazelle. It means letting myself take a minute to celebrate when I work out a hard problem and patting myself on the back when I fix a sentence. And it means taking breaks.