Let me put it this way: The brain is a muscle. It burns calories just thinking. Writing requires far more, and far more intense, thinking than other jobs. Writing is DEFINITELY work. Could you drive 60k nails and not be tired? No. You'd be dead tired from swinging the hammer. Same thing here. You need a break. Release one more chapter and include an authors' note informing them that you need a break and you'll be back when you're able to. Explain that the stresses is affecting your health (brain fog and headaches are health issues. remember, the brain is a muscle. Brain fog is equal to muscle fatigue, headaches is equal to muscle aches).
You can also give an expected return date. If you need longer, fine. Leave a note on your wall. If you can return sooner thats fine too. I'd aim for two weeks. During this time, relax. During my breaks, I still write, but more to not get out of the habit. And I never write things that I expect to post. Just inane little babblings, stories that would be against ToS for one reason or another, etc etc. basically just things I WANT to work on. You'd be surprised how relaxing that can be, rather than writing in the world you've created that you're now expected to write in.
I'd recommend learning a new skill for your first break. A break I took years ago, I learned to throw playing cards. Got pretty good at it too. My first break after I started writing back in high school, I learned to flick pennies (Like, snapping my fingers, but using that force to send pennies flying at a target). I've learned close up magic, I've studied blacksmithing, HEMA, archery, target shooting (guns), various crafts from strange material (made a bow out of PVC and fiberglass, made a bo staff, made tonfa, etc).
I also took up DND during a break 7 years ago as DM. It really does help writers learn to write better in some ways, but can also create bad habits in other ways, so proceed with caution with it. Point is, do things that help you relax but that also keep your brain working. If you don't it'll be harder to get out of vacay mode and back into work mode.