I feel your pain mate. I do shifts and there are nights when I don't sleep at all and don't make up for it during the day. And then it seems the more tired I get the less I'm able to sleep.

I will say that it doesn't seem to affect my training and growth like all the 'experts' seem to say it will!

Finally cracked it last week. Took 5g valium and three large glasses of white wine and slept for about 7 hours. As I don't really drink alcohol I can't see me making it a regular routine.

As for OTC stuff, I've never found anything that works