Sandi...I took Melatonin in rehab and for a few weeks upon discharge. The DR there said to buy the kind that was "pharmacuetical {sp?} grade" which, I think, means it doesn't have any animal by-products? {not sure about that}
It seemed to work pretty well for me but I was also taking alot of warm baths so that helped alot too.
Good luck finding something that works for you...I know the Tylenol PM isn't that good for your liver but if you only use it every now and then, it shouldn't hurt.
I would also hit up the local Healthfood store as they usually have several good options to try!
Good luck!
Jane