In the past, I had all sorts of advice I could give you to feel/be more productive. Now, having experienced severe burnout that lasted several years—that still affects me, and may do for the rest of my life—

My advice is to listen to your body. It is telling you there are more important things than productivity, at least right now. Take a break! Whether that’s a nap, a day off, a long weekend, whatever you need. You’ll be glad you did. You may very well be more productive in the long run if you do.