For the past month or so I have only been getting around 4.5-5 hours of sleep a night due to some schedule changes (i am trying to fix this of course), yet when I wake up I'm not as dead tired as I would have presumed. Since I am able to sleep in on the weekends, I did so last weekend, and this weekend I think I got 7 to 8 hours a night but surprisingly feel 10 times groggier than with the less sleep. I can barely keep my eyes open and feel like falling asleep while standing up.

I know that over sleeping is definitely a thing, but I highly doubt that's the case since I have been getting such little sleep in the past month and the most I slept any of the nights was about 8 hours.

I'm assuming my body is just angry with me for getting such little sleep lately, but I'm really curious why a few extra hours is causing me to feel 10 times more tired.

And as a side question is there any good way to actually make up the sleep I am losing if it's not on the weekends? I'm concerned for the long-term effects.