Sometimes I feel the same way. I tell myself that I can relax and lie down and watch a movie, but I rarely feel comfortable. For some reason I feel extra bad especially nowadays. I hope to get rid of this feeling soon. This is something I started to feel especially in 2022 and 2023.
don't feel bad about not being able to rest. You have to rest in order to perform better and at your best. Anyhow, I think that it's best to give a day or two to rejuvenate and then work hard again. That's what I learned these past few days.