Hey Sleepy: Dave was giving you the straight scoop when it comes to Diphenhydramine. It's the active ingredient that comes in Benedryl that actually makes you sleepy. You can buy it over the counter in 25 and 50 mg doses. Before I started having all of my medical problems, I use to buy the generic version of Diphenhydramine, 50 mg, for sleep. If you can, buy the generic as it costs about $2.95 for 50 tabs, where the brand Benadryl will cost three or four times that amount. Don't worry about a script from the ER, you don't need one.
Most people on these boards are probably too young to remember, but years ago (probably early 70s) Benedryl was a prescription medication. Then the FDA approved it for OTC use.
I doubt very much this med would go against your pain contract.