It's kinda a common personality trait with AF to know you should go to sleep but don't. We have a tendency to want to stay up late and fill our days with task we need to do. Part of it comes from anxiety too. The fight or flight response keeps you alert and especially at night.
Believe me I have felt the need to get myself in bed by 9 but it always ends up being twelve. Your also right in that your body needs lots of sleep to repair it's self. But you can catch up on lost sleep to a degree. I know being able to get more sleep has healed my body more. It always your adrenals time to rest and rebuilt.