But - you did say that something happened three weeks ago.... So, it's a bit confusing that you now say that nothing happened?
No, your symptoms are not word-for-word, exactly as listed in the symptoms in that article.
However, you are having problems that can be attributed to the power manager.
So - you should try that reset. It either helps, or doesn't, and you will not hurt anything to try the reset.
Another possibility that you can try, is to boot to your Recovery partition and reinstall Lion.
That will help clear out possible "cruft" that might accumulate in your system. Run your Software Update then, to make sure that all is up-to-date at that time. The OS X reinstall simply reinstalls the system on top of what you already have. Your own files and apps should not be disturbed.
One or two restarts will rebuild your system caches, and you should be good then.
If you prefer not to do a full reinstall, then just download and install your current OS X combined updater. That won't be quite as effective as a full reinstall - but may also get your sleep situation working more effectively. You can get the Lion updater here:
http://support.apple.com/kb/DL1399
In case you question using that updater - reinstalling an already installed, current update (with the combined updater) has been part of successful methods for troubleshooting odd problems that suddenly begin happening on OS X for at least the last 10 years.
Give that a try, and let us know how it goes.
