I know exactly how you feel, as I've been in the same boat off and on for about 10 years.
At times I have thought how easy it would be to step in front of an oncoming subway train. I'm not really suicidal, just find myself thinking that a nice long coma would feel pretty good.
I still don't know exactly what the problem is, but I do know this:
-alcohol makes it worse. WAY worse.
-sleeping pills have no effect, nor do any of the herbal suggestions, like valerian, skullcap, etc.
-I have no problem RELAXING. I am not under any undue stress.
I get to the point where sleep is just within my grasp- lying in bed, brain and body relaxed, but something keeps me from turning that corner into sleep-land
-I do get something from lying in bed in that totally relaxed but still-conscious state. It's not as good as real sleep, but it is better than nothing.
I eat healthy. I had all my mercury fillings replaced. I have been doing all kinds of cleansing (bowel, liver, etc)-things have steadily improved- but at the same time I also started taking Paxil.
Now I know people will have a fit about that, and yes I know its not good for me, but it really has made the difference between life and death (or no life at all) for me. It doesn't solve the problem, but my sleep is tremendously improved when I'm taking it. For that, I am willing to spend extra time cleansing my body and hopefully eventually I will be able to stop taking it.
FYI- I have been diagnosed with fibromyalgia, which my doctor belives is primarily a sleep disorder which then leads to muscle and bone pain as a result of a lack of deep sleep when body repair takes place. All very interesting but he can't really help me, except to prescribe pills.
I hope you are able to find something that helps you sleep.