You may spend almost every waking hour in a "manual" mode, consciously filtering out the roar of life that others ignore. Your system continues registering what others naturally tune out.
When you feel "wired but tired"—like your body is buzzing but you have no energy.
When your brain feels like a computer with too many tabs open.
If you feel scattered, dizzy, or like you're "floating" outside your body.
One of the most painful parts of burnout is the loss of what we might call care capacity. You may still care in theory, but your energy to act on that care feels gone.