Just to repeat:
1) Exercise- lots of time we think we are tired, but it is our minds that are tired not our bodies. Especially with stress you mind might be working overtime, but your body physically may not done anything strenuous.
2) Relax- Make a cup of something warm and go sit somewhere outside. Wheather its a warm brandy or just a cup of cocoa the important thing isn't the drink it is doing something mundane and easy. This tends to help me, but with yours being stress this may just give you more time to think about it all. It seems to work for me though.
3) Conditioning- I am proof it works, maybe a little too well

I used to have problems sleeping, and was told by a doc to stay away from the bed but for sleep. If you need to read before bed place a chair some place close by. Read for a bit when you start to feel drozy the two stumbles it takes to get to bed shouldn't be enough to wake you up completely. This doesn't mean that you can't do other things in bed, but for a while keep it to sleep till it starts registering bed=sleep. Again can't say this would work for you as everyone is different.
4) If this keeps up as someone said you might think about seeing a doctor. It could be a chemical imbalance that just needs to be worked out, or could be just a little bump in the road, or something bigger. A few nights sleepless is one thing, but a month or more of sleeplessness is more serious.
5) I have to second the thought of staying away from the sleeping pills unless a doctor tells you to try one. Trying it once though isn't a big problem, just watch how many and how much. Sorry, just saw some bad cases of over use.
Best of luck to you, and hope all the things that are causing the stress ease up a bit or work out for the best.