Can't stop getting annoyed at my boyfriend for every little thing

My boyfriend has been pissing me off lately. We're long distance and it sucks, especially bc he sucks at communicating over the phone bc he's pretty forgetful. A lot of the time he'll take hours and hours to respond to my texts and sometimes doesn't call me when he says he will. This is the only thing we every disagree over and it's SO annoying. I just want a few texts to know he's thinking about me. Now when he tells me he's busy but has been sitting around all day (and wouldn't text me) I get so pissed. It literally annoys the shit out of me and I don't know what to do anymore. I know that I'm kind of being a bitch but I'm honestly fed up. We've discussed this again and again. Help?