<Snipped quote by Intrepid>
I imagine being sleepy is similar?
No, not at all. Instead of pain or weakness, imagine that if you didn’t sleep in intervals that your body needs, your ability to process things slowly gets worse and worse, and in general your body eventually hits a point where it can just start doing less and less in all regards. Also you get this really really strong urge to sleep the more you go without it, to the point it’s very difficult to control when you go long enough. Sleeping involuntarily is a thing that happens.