Am I wrong to be irritated?

My husband works out of town. He’s an electrician. He leaves early in the morning like in the wee hours and I get home late at night from my work and he’s also in school so we don’t have a ton of time together. I call him once a day on my way to work, we speak for 10-12 minutes depending on my drive and he’s texts me during the day when he can. If I have something important at other times during the day (which isn’t often) i call and if he doesn’t answer I call again just so he knows it’s fairly important and to call me back as soon as he can. Well today I call him, I had a time sensitive question to ask him. He doesn’t answer so I called right back and just let it go to voicemail again. Well then instead of a call back I get this big long text message from him about how he’s at work and he’s busy and he can’t answer his phone and blah blah blah. And I’m like how long did it take you to type that message out when you could have hit the button on the headphones that I know are in his ears because he listens to podcasts all day long….. it was literally a conversation that would have taken less than a minute to discuss and instead of answering he sits and texts me back??? It doesn’t make any sense to me but he’s furious that I got upset over him texting me back instead of answering a call. I’m also 900 weeks pregnant and he’s hours from home - not that anything was wrong this time, but what if it was?? Like would he be pissed if I called to tell him I was on my way to the hospital? You can bet I wouldn’t stop at just 2 calls.