Tomorrow is our big 20 week anatomy scan. I am high risk for preterm labor so they will be checking my cervix too (they check it every other week)

My SO has known about this for weeks. We dont live together. He doesnt work. We had planned for weeks now for him to come stay with me tonight so we can get up and go to appointment together in the morning. He knows its a big appointment. Well today I couldn't get in touch with him all day, turns out he slept all day. So finally around 6pm he messages me and says he woke up, is going to eat and then head this way. After that he goes silent again. I continue to message him and get no answers. Finally at 9:45 I call him he doesnt answer phone but messages me back a couple minutes later and tells me to go on to bed he will just be here in the morning (mind you he's not reliable when it comes to early morning events, another reason he was coming to stay and go with me in the morning. ) I had been sitting there for almost 4 hours waiting for him to walk through the door to find out he had went back to sleep not caring apparently about me waiting on him only to wake up to tell me he will just come in the morning... this really really upsets me. So I call him upset asking whats going on, he says he fell back to sleep for another 3 hours after eating. Instead of just getting up and coming over like he promised he would for the past 4 weeks. I am obviously upset on the phone and tell him forget it and hang up.

He then messages me and says he can come now if I want him to or he can come in the morning but cant do both and that I need to get my hormones in check and stop "forcing" myself to be upset over this. Am I overreacting by being this upset over this?

All he does all day all week is sleep, play video games, refuses to find work. I dont understand why tonight of all nights he couldn't pull himself together to stick with our original plan and come be with me during this important time. I am shaking from how upset this has made me. And now I'm wondering am I just overreacting because of hormones or do I have some reason to be upset?