Generally, I find watching TV and sitting in front of the computer late in the evening doesn't help (apparently, our brain interprets the "bright light" from the screens as daytime). Also, I find herbal teas with valerian, hops, lemon balm help, as does listening to some relaxing music in bed on my earphones - and NOT concentrating on the thought "I MUST sleep". I also find meditation techniques, like watching your breath and relaxing every bit of your body deliberately seems to help. And the smell of lavender on my pillow - couple of drops of essential oil is usually enough. Good luck, let us know how you're doing!
Chamomile and lemon tea has a wonderfully soporific effect! I've also been counting down in my head from 100 lately and that seems to be working (I've been having the same problem), although I was very disappointed the other night when I got down into the 70s... lately I've been lucky enough to fall asleep before the mid 80s.
Do you think things like streetlights outside or anything flying overhead could be affecting you at all?
I agree with lavender, it's great for relaxing. I try to stay caffeine-free from early afternoon and find that reading a book in bed makes my eyes 'go' and helps me feel sleepy.
If Willow's suggestions don't help then I'd go to the doctor, 2-3 hours of sleep isn't much at all.
Keeping a regular nighttime routine - even if you're not tired - is the key. Again, lavender will really help. Avon do a spray lavender scent, which you just spray on your pillow. Drinking a milky drink before bed will also help. And, at night, try to stop thinking about going to sleep. I write this, because the more you push yourself to sleep, the harder it is to fall asleep. It is a paradox, I know. Do try sleeping pills, as well. I'd get proper prescription pills: not herbal remedies. Do also get up at the same time every day: even if you're tired. Do also keep as active as possible in the day. The busier you are, the easier it will be to fall asleep at night.
I think Willows21 has given you some great advice. I really hope you find something that works because I have no idea how you manage to function on so little sleep - I can't cope with tiredness at all. If your still having trouble over the next week or two then you MUST speak to your GP - insomnia certainly isn't too trivial to see your doctor about.