I always have this problem.. I read ages ago that eating some turkey & milk helps if it's possible about 30 minutes before you sleep. Try not to drink much caffeine past like.. Dinnertime. If you're really having that much trouble, you could always try and purposely crash yourself..

- Get a nice big can of Relentless
- Down it at about 7PM
- About 10/11 you will just want to die
- Go to bed, and you should fall asleep

Don't forget about making your room comfortable to sleep in though.. Get rid of all those little annoying lights from things like TV, Laptop etc. Remove any noise (including children. REMOVE THEM). Don't sleep in a dirty room though either, clean it, make it nice and cosy

If it's REALLY that bad, there's also the more extreme option of staying up through the whole night, and the next day too.. When it comes to go to sleep, you'll be freaking exhausted let me tell you, hah. Make sure you wake up fairly early the next morning too, so you haven't 'slept it all out'.. Get me?

been awake since 3 pm 2 days ago.

it aint nothin.

I know how you feel. I have Chronic Fatigue Syndrome AND insomnia. Works really weirdly. I can be absolutely exhausted, but not sleep for 5 days straight. Then I sleep for 2 days straight. It's annoying and has screwed my inner clock up horribly.
The past fortnight or more, when sleeping (semi) regularly, I've been falling asleep at 7am+ and waking up at 2 or 3pm.