misschief, feel so strongly for you, know exactly how you feel. have had bad insomnia over the years, worst was during my 1st pregnancy. COULD NOT SLEEP, no matter how tired I was, went to gp who gave me sleeping pills under duress, i was triumphant, went home thinking it was all going to be better, and....
Nope. Not a sausage.
What has helped? I hope this random list of things don't make you want to hurl the computer across the room (I never forget going to see the midwife in tears, explaining how i just couldn't sleep, how I didn't know how i could carry on, etc, etc, etc... and she said "have you tried a cup of warm milk before you go to bed?" THUMP!!!!!)
Back Flower Remedy "Oak" (for exhaustion due to chronic sleeplessness)
Listening to the World Service/R4 (sometimes bored into sleep submission)
Rescue Remedy Night Time formula
Coffea (homeopathic remedy for over active mind, take during the day, before you go to bed, and when you wake up at night).
Sounds also as though you have some anxiety/depression issues (of which insomnia is commonly associated), and I was doing some research into this myself earlier this winter, as I think I get SAD. I found this and wondered if it might be something you would be interested in trying? It is available in the UK as well.....
Have had acupuncture in the past too (not as treatment for insomnia) and found I slept much better as well, but don't know if it can tackle it specifically. Eventually, with the pg insomnia I mentioned earlier, I took absolutely EVERYTHING I was allowed to take at once, and things did get a bit better (herbal remedies, homeopathic and bach flowers).... really hope you get some sleep soon, it is completely crippling and you don't feel human in your current state. Good luck.