Is this a normal part of a relationship?

Me and my boyfriend have been together for a year now. Everything was fine in the beginning, I was laid back and chill, nothing really upset me. We don’t argue or anything, nowadays I just seem to be passive aggressive toward him and give the silent treatment. We have good times together and I enjoy seeing him when I can, but I find myself getting mad at him more often and sometimes it’s a selfish reason too. For instance, he was working 9 hours that day and didn’t eat and was tired, usually, we talk late at night through skype, I was mad at him for being tired and not talking to me. We were skyping, but he was silent and apologized that he’s just tired but still want to know how my day went. This is my first real relationship. I usually break it off with people within a month because I get bored.