I hesitated before opening this thread as it might sound dumb but it is true.

Why am I fatigue during daytime and energetic during night time?
Are there humans destined to be nocturnal like owl?

If you are energetic during night time, i suppose you don't have a fixed sleeping schedule?

Have you tried to cut down electronic devices usage at least 2 hours before bed time? Another factor is probably the weather is cooler during night time and less noise/ disturbance but that shouldn't be a factor of fatigue during day time.

btw, im not from medical field or any that is related.

Check your eyes.

Me i notice depends on my food intake during the day. I have similar issue but i control with food as in eat light helps the fatigue but this is what works for me.

sleeping schedule fixed
but did not try on the 3 hours before bedtime, it might be related, need to drill down one by one
I went for checkup last year, all seems good

hmmm, will pay more attention to food intake
thank you for the suggestions

I think all humans are programmed to work at day, sleep at night. I would think it is mostly due to environment and lifestyle changes that the sleeping cycle is affected. We all have a circadian rhythm and extra light sources, eg. computers and phones will prolong the waking period and eventually your body will become accustomed to the cycle.

If your lifestyle is as healthy as it gets and still having such problems, better to check with a doctor, could be due to other unforeseen factors.