My Mother in law uses something called Midnite... I think you can get it at wal-mart. She really likes it, but I have not used it so I cant really give more input than I already have.
50 mg of Benadryl (diphenhydramine hydrachloride) which is the active ingredient in 99% of all sleep aids works well for me. Add 3 mg of melatonin and sleep like a baby. You can get the generic benadryl at Wally world (or similar store), for about $4.00 per hundred, or $6.00 for a double pack. I suggest you try using it at home first to make sure you have no unwanted side effects.
I slept under an open tarp solo a couple weeks ago. At 1am I had a mouse run across my face. Lets just say I am not sure when sleeping under a tarp only will happen again between that and the bugs biting every piece of exposed skin. I also put earplugs in my bag after that trip. I live in a town of 400, so its very quiet at night but any sound wakes me. Call me what you will, id rather be oblivious to the sound once i go to sleep, i can enjoy it plenty up until that part.
I sleep like a baby in the backcountry, never have had a problem.
I'm usually tired, just fed ... and normally take a Tylenol ER and many nights have a snort or few of fireball before bed.
Which I'm sure helps.
Sorry others don't enjoy similar bliss.
Hunt'nFish