I was having issues sleeping a few months ago (I think due to stress at work) and a co-worker recommended Valerian. It is a natural supplement and you can find it pretty much anywhere that sells vitamins/supplements.
I think it works great. I take it about 1 hour before bed and I am able to fall asleep and stay asleep and most importantly, I do not feel crappy the day after taking it.
Hope you are able to get to sleep before your trip and get it started right!
Enjoy and Sweet Dreams..