The time seems to pass much faster when we sleep because we are unaware of the time passing.
The time actually passes at the same time every night and everyday.
However in the daytime when we are awake we are aware of the time and when we're busy the time seems to pass fast.
When we are bored and not doing anything then the time can seem to pass by really slow.
But when we are busy then we are not paying attention to the time and so that is why time seems to pass so fast when we are busy or are having fun.
When we think about the time passing then it seems really slow but in reality it passes at the same time.
It's just our perception of the time and since we're not conscious when asleep we don't notice the time passing and before you know it it's time to wake up.
When you sleep for those 8 to 10 hours it seems like 30 minutes to an hour at most.