I would not recommend
You have to remember, everybody is different, physically and mentally. Diphenhydramine overdoses is difficult, extremely difficult.
Within your first 300-400 mgs, your stomach will feel like a void, turning in on itself, if you haven't vomitted already. Vomitting is not the only thing your body will try to do. You may experience profuse sweating, seizures, or any other side effect; from your body trying to filter out medications.
I have mixed Hydroxyzine with alcohol, and other medications that have a Diphenhydramine content. I continue to take Diphenhydramine and other medications regularly, as normal sleep is unnatinable without it. I take 200-350 mg daily in order to sleep.
My worst experience, with other medications and alcohol, my walls looked like it was covered in ants, I saw black lines flying at me, and black lines coming out of objects from my room resembling spider legs. When I looked towards the light, I saw shadow of spiders crawling under my eye or clawing at my eye.
tldr: you'll probably wake up really drowsy and remain drowsy for a day, or two, sweating, or vomitting, and having a few seizures.
I highly recommend you to do your research, and act with logic, not emotions.
You must understand that sometimes better is not attainable for some, because some do not know the definition of better; find your destiny, or interest, to live or die.
Die logically, not emotionally. After death there is nothing; nothing ever mattered/matters.
I personally wouldnt die crying, even if I was physically incapable to.