I'd normally be very reluctant to suggest turning to drugs to solve a problem like this. I'd be even more reluctant to suggest a highly addictive drug, such as diazepam (which is probably better known as 'valium'). However, I think that my own story might be relevant:
Many years ago, when I was at college, I was experiencing real problems getting any meaningful sleep. After over a fortnight with no more than a few minutes 'napping' at a time, I went to the college doctor. He gave me a short course of diazepam. I only took the tablets for two nights but that was enough to 'break the cycle' and return my sleep patterns to normal.
So perhaps something similar might do the trick for you?
Have a word with your doctor. You've got nothing to lose and you might feel far better very quickly.
Chris
PS: Of course, you might actually be suffering from a virus, or even a condition like CFS
http://www.nhsdirect.nhs.uk/articles/article.a spx?articleid=102
(although that's extremely unlikely) but your doctor's definitely the person to ask.