Is it okay to get <5 hours of sleep during the school week?

No, its not okay... Health is more important than school...

Actually, different people have different sleep needs. If you can function well with only 5 hours a night, and don't have any serious side effects, then you're fine. At least, I am assuming you were talking about 5 hrs a night and not 5 hours in an entire week. Because if it's the second- you are heading for a mental and physical breakdown, which would definitely not be conductive towards schoolwork.

No no its so not healthy u need to be getting at least 6-8 hours of sleep just try getting 1 more and you will be fine

A person needs eight hours of sleep or more to get through the day if you sleep less eat breakfast and plain coffee no sugar it's healthy google it.

It's not okay at all especially when you do it everyday. I sleep less than 4 hour everyday. Sometimes 2.30 hours.