Benadryl is not "addictive" in any reasonable sense of the word.
Could you become psychologically "dependent" on it? Well, sure.
But, guess what? People become psychologically "dependent" (i.e., it causes discomfort to go without) on all SORTS of routines, e.g., their usual breakfast, their TV shows, etc.
Unless you want to stretch the word to its breaking point, making it useless and non-indicative of anything other than a facet of human nature that plays a role in everyone's daily life, you cannot begin to apply this to taking two Benadryl a night.
Just stop taking the Benadryl and you'll get over it after a few days.
The fact that people who have difficulty sleeping become used to taking a medicine which helps them sleep, and have difficulty imagining sleeping without it does NOT make it addictive in any reasonable sense.
It just means you fear going back to being unable to sleep! (After all, if that was your previous state, how can you attribute a recurrence of that state of affairs as an effect of cessation of the drug?)
It's psychological -- you have no physical dependence on Benadryl (again, without stretching the concept of physical dependence even further than the concept of addiction).
So, to put it simply -- you're fine. Just stop. Benadryl is NOT like Ambien, benzos, barbituates, etc. It's all in your head. Be glad you don't have a real drug dependence or addiction.
FWIW, I used to take Benadryl to sleep at night on a daily basis. I just stopped at some point. I'm sure I took Benadryl at least as long as you have, and it's just an antihistamine, you quit it, and that's it. Done. That's why it's available OTC in even the prohibitionist USA.
The fact that I remember none of the specifics of the stopping at all -- and that I never even decided to stop, but rather that it just happened organically, if you will -- is indicative of just how non-existent any sort of diphenhydramine addiction is.
Again, there is nothing reinforcing about diphenhydramine besides the fact that it allows you to sleep. You're just worried about not being able to sleep (and about the ridiculous idea that you're taking an addictive drug)! So, stop worrying, and start sleeping without it. Whatever you may have heard about it is wrong. It is most certainly not addictive (although people become psychologically dependent on sleep aids, this is simply because they fear returning to being unable to sleep [benzos, Ambien, barbs, etc., are different -- they actually do cause a physical dependence, as well as a psychological dependence]).
Or, alternatively, keep taking it if you still have trouble sleeping without it and it makes your life better!