A lack of sleep can make your appetite change quite a bit, which is a bad result because good nutrition is essential for your body and mind to function. If you don't sleep enough, your body gets confused. If you're awake for longer periods of time, there'll be more moments on which you're hungry, and on different times as well.
Dark circles
We've all had them at some point, right, these evil things right under your eyes! Sleep is important to prevent severe puffiness around your eyes as well.
Learning is more difficult
Your ability to concentrate gets much less when you don't sleep enough, which isn't nice.
Deregulated menstruation
Sometimes, an irregular sleeping pattern will affect your period as your hormones are confused.
Dancing text on screens
Sometimes, you'll see text dancing around on your screen because you're that tired. Ain't that weird?
Increased risk of becoming ill
Enough sleep is essential for your immune system. It ensures that your body can ward off infection and disease. Less sleep will weaken your immune system, making you get ill much quicker.
Driving becomes rather dangerous
If you've had very little sleep, it can be quite dangerous to drive a car or any vehicle for that matter. The effects of too little sleep are comparable to the effect of four to five alcoholic drinks!
No productivity
Without sleep, you won't feel very productive. Time to get some sleep!
Hangover
Even without alcohol, you can have a hangover. Anyway, you'll feel like you have one. Headaches, sensitivity to bright light and cetera.
Now, get back into your normal sleeping pattern, go and catch some sleep!