Is it bad to take benadryl every night?

I just can't sleep anymore, so I've been taking 2 benadryl pills every night to help me sleep. I'm not sure if it is harmful to take it every day or not? I don't have allergies or anything, Im just using it to feel drowsy, but now I notice that I wake up every morning with a sore throat... is this because of the benadryl? Are there any other bad side effects it could cause? I am really having trouble sleeping lately, so I have to take something.