Diphenhydramine Hydrochloride Causing Sleeplessness

In the past it was recommended to me to take diphenhydramine hydrochloride (allergy pills) to help with sleeplessness.  Although it may have helped in the past, lately everytime I use Diphenhydramine Hydrochloride (whether in Tylenol PM or in allergy pills) to try to help me sleep, I end up having a very restless night, waking up several times during the night.  Sometimes I may have had a glass or two of wine before using them, sometimes not.  I still would not be able to have a restfull sleep.  Is there something in diphenhydramine hydrochloride that may actually cause insomnia?  Recently, I have been trying some natural ingredients (chamomile, melatonin, etc.) that seem to allow me to sleep much better so I'm thinking it must have something to do with the ingredients.