Chronic insomnia sufferer, looking for some help getting to sleep?

[spooky]

I've suffered chronic insomnia related to bipolar disorder for a number of years. I've been through two sleep studies. For a while, I was being treated with Ambien - and this worked well for me. But now I have no insurance, and the insomnia is back with a vengeance.

It seems that I have to keep myself awake until I'm ready to drop dead from exhaustion before I actually get sleepy enough to rest. Over the counter sleep medications don't offer any kind of help. Once I actually fall asleep, I can't stay asleep, usually only resting between 3-5 hours.

I'm getting very frustrated at my inability to get a full night's rest, and my lack of options. I've tried OTC sleep aids (3 different kinds), melatonin, some other herbal supplements, chamomile tea, cutting out caffeine, warm milk, exercise... I'm at a loss.

Suggestions will be appreciated, thank you in advance.