Me personally? By day 4 I would be horrible and desperate for sleep.
When I am overmedicated in thyroid meds I can handle it better, but I am still not doing well and it becomes hard to function at my top game. Harder to focus, grumpy, my eyes feel like they are rolling in my head. My mom used to say that about her eyes, now I know what she means.
In general, not allowing people to sleep is a torture technique. Working moms of infants all over the country are semi-tortured. I don’t mean all are sleep deprived, just that a lot of them are.
Some people naturally need less sleep. I think it was Martha Stewart who I heard years ago say she only needs 6 hours a sleep per night. That’s very little on a consistent basis (for people under 65) if she isn’t napping also.