Am I overreacting?

Almost every time my boyfriend gives me a specific time of when he will be back, etc, he usually never is. And this is not a one time thing, or a every once in awhile thing. when he leaves and says "I'll be back in an hour" it won't be maybe an hour and a few minutes, or an hour and a half. Hours later he will be back. It really frustrates me. If for any reason you need to be longer than you said, why can't you call or text to let me know? Just today he said he'd be back in 20 minutes because he had to go get a phone charger from his house. This was almost two hours ago. I just want to hear your opinions, do you think I'm overreacting? Maybe it is just me. It just drives me crazy! 
Maybe it is trust, being paranoid. I can't even count how many times he's lied to me.