I posted a thread on something similar in the medical & health forum, and got some advice there so you might want to take a look.
Being an Aussie, you should check
Civil Aviation Safety Authority - Home, they should have a list, or you can call up and ask about any medication you are considering taking. They can tell you if it's allowed, allowed only with prescription or not at all while flying.
One thing I did read recently that sounds a bit crazy, but actually worked, is to use a cold pack on your head for a for minutes, apparently it cools your brain down a bit and this can help some people fall asleep more easily. Weird but true, I tried it!!
A friend of mine who is qualified in this sort of thing told me that the melatonin you get commercially in Oz is pretty much useless & a placebo in the amounts it's sold in. He said the ones from the US are better but are not allowed for sale here so I guess there's a reason for that. Getting some sun during the day will have the same effect and can be helpful to 'reset' your body clock. (It can also prevent becoming vitamin D deficient which is common in winter and can give that 'constantly tired' feeling)
I've been finding that if I get up early on my last day off as suggested that I've been sleeping better at night.
Blocking out all light (however small) seems to help too. You might need to use eye shades to start with, after a couple of years I could fall asleep in bright daylight and have only recently been having problems getting to sleep.
Hope you find something that works & sweet dreams!!
