Insomnia Again!

I'm an insomniac; officially. I've been drifting in and out of insomnia for the past year or so. It hits me in phases, and I don't know when it'll occur or why am I sufferring from this illness. What I do know is that I should definitely stay away from caffeine. Coke, all sorts of tea (even bubble green tea!), green tea ice-cream, and of course coffee will make my brain extremely alert. Insomia comes and stays for up to a week, and then it usually leaves me alone for two months or so before it creeps onto me again. The last 4 months I was left alone, to much relieve. Perhaps cos the long holidays were stress-free, or maybe the regular gym sessions helped. I'm pretty much clueless what causes insomnia in me. It's seriously affecting me alot, especially when I'm one who needs at least 8 hours of sleep everynight. Tonight, it's my 7th night wide awake at this weird hour. Just when I needed some wine to make myself feel drowsy, I ran out of it. Damn! My eyes can barely remain open now, yet when I lie on the bed, tons of activities are carried out in my brain. What is wrong with me??!!