If your brain felt full before you even got out of bed, that's not a character flaw. That's an overloaded system doing exactly what overloaded systems do.
The pressure to "make today count" is usually the same pressure that drained you in the first place. You're allowed to put it down.
Some days the goal isn't to get ahead. It's to not add anything new to the pile. If you get through today without piling more on, that counts. That's the win.
Slow is allowed. Bare minimum is allowed. Neither one makes you any less.