Benadryl is the real "sleeper" OTC wonder drug. It has a relatively low potential for abuse according to several pharmacology books. It is considered a mild sedative. Diphenhydramine, the active chemical in Benadryl, tends to activate the psychological addiction rather than the physiological aspect. Translation: a person might feel like they need to take it when they really don't, just to help them sleep.
I tend to get hooked on it periodically. You might want to speak with your doctor about a prescription for a different medication. Melatonin might be a good alternative too, but only when your sleep cycles seem irregular.
*I'm neither a physician, nor a pharmacist. So it's best to get a professional opinion.*