ditto Peter T. you can also drink something warm right before bed (beware: it'll make you want to go to the bathroom, too).

is it your symptoms that are keeping you up, or is the insomnia a symptom in and of itself? if the former, you should try to relieve those as best you can. sleep propped up a bit on pillows to help your nose drain; make your bed extremely warm and extremely soft to make the aches more bearable; don't be afraid to fall asleep with a sugarless coughdrop melting in your cheek, especially if you're propped up. when i awaken, it's always exactly where i left it but much smaller.

most of all, give yourself every possible opportunity to sleep. go to bed, kiddo. stay there.

*mops your fevered brow, virtually*