I’ve not slept for 3 weeks.
How can you stay away for that long?
You can’t. Tis a joke. The most any human can stay awake is about 11 days, and the effects of attempting to go this long can be life-threatening, and if it doesn’t kill you, it can cause permanent physiological damage. This is why preventing prisoners from sleeping is considered a form of torture.
I thought I saw somewhere that if you go without sleep for long enough(much shorter than 3 weeks), that you start having hallucinations.