Why this happens??

The less I sleep the more awake I am, the more I sleep the less awake I am. I’m able to survive on 4 hours of sleep for a total of 3 days.

Because oversleeping is not good either and if you wake up with an alarm your sleep cycle might be at its lowest point. Try to aim for 8-10 hours if you’re a teen and 6-8 hours if you’re an adult. But I can’t say much, being a horrible insomniac myself.