I am I over reacting or does my husband need to be more understanding?

I am pregnant and I went to a doctors appointment today that my husband couldn't make. I would have expected him to call me afterwards to see how it went but he didn't and he didn't call me all afternoon. I started calling him when he usually gets of work with no response to his personal or work phone and no response to my text. I started to get worried. When I finally heard from him he was yelling at me about how disrespectful it is to call him over and over (I called a total of 5 times in 2 hours) and that he was with his boss and couldn't answer. My argument is that I am pregnant and need to be able to reach him at all times. What if was an emergency...If he couldn't talk then all he had to do was answer once and say that or text it to me so I knew he was ok. I am pretty sure his boss would understand. If he just told him that I had a doctors appointmnet and he need to make sure everything was ok.