It's hard to not worry about going to sleep when you know you can't. Telling someone with anxiety 'don't worry about it' isn't the solution. It's innate in their genetic makeup, they WILL regardless.
Take half a xanax, valium, your body will relax enough so sleep can begin. Or, try Lunesta. Just don't get hooked on the stuff, it's addictive in the sense it WILL put you to sleep, but if you try and go 4-5 hours on it your day will be fucked up. In general, use it as a last resort.
I agree with all the advice on physical activity, etc. but the guy can't just go to the gym, work hard, and expect to sleep that night. It will take awhile for your body to adjust to the new stresses you're putting on it. In fact, you probably WONT sleep as your bod will be in shock for a few days. That's ok, ride it out. Ultimately, the workouts will reduce the stress levels that are keeping you up and you'll fall into a new rhythm where your head hits the pillow and that's all she wrote.
But, if the stress of sleep is causing you anxiety, severe strain, see a Doc, get xanax, or lunesta, etc. and get some sleep for a few days. Your psyche will be relieved that there is a pill you can take that will let you actually sleep. Continue with the workouts, push hard, and you'll be sleeping naturally.
Valerian root, etc. is a bunch of hooey in my opinion. It works if you have mild insomnia or arent really stressed about sleeping (my opinion). If you have heavy insomnia, it won't do crap.
Good luck, let us know how you progress!
(BTW in the past when I had insomnia, I'd get up and go into the home office, and got some serious shit accomplished. I figured if I was gonna have it, I might as well do stuff I'd always wanted to do. Of course, I was a zombie the next day. But I've been lucky in that when I have a night of insomnia, I'm so zoned/tired the next day I always fall asleep the 2nd night early, then the 3rd night it comes back, etc. I've never had it more than one night in a row)