Am I jealous or do I have a reason to be pissed?

So in six days, me and my boyfriend will be 1 year and 8 months together and I still don't fully trust him. He's lied and hid things from me before and I'm not gonna lie, I have gone through some of his messages in the past. I HATE doing it but I'll never know because he's always hiding things from me. I also know that he will never cheat on me but he just pisses me off sometimes. Well today, he randomly told some girl (one of his "friends") that he was going to pull an all-nighter with her through FB and the phone. He has never offered to do that with me and when I beg him, he falls asleep not even 5 minutes later. So he's messaging me and her at the same time. She agrees to do it, so his next message is a good night one and he says he gonna go to sleep. That got me mad. Am I jealous or that reasonable enough for me get mad?