Am i wrong?

So my bf went to work today and was supposed to get off at 6pm it’s now 9pm and he’s just now walking through the door so i am really pissed. His phone is off and he rides the bus. But we text all day while his at work because they have WiFi so i told him to let me know when he is about to leave and he never does. And the bus is usually a 15 minute ride. He has the bus was late but 3 hours late? Now hes pissed off and doesn’t want to talk. Also I’m 38 weeks pregnant and could go into labor at anytime. This is the second time he’s come home hours late and not let me know. I’m only upset because that shit is scary. The only thing going through my mind is he’s laying dead in a ditch somewhere and he can’t even send me a simple text to let me now he’s okay, then wants to get pissed because I’m upset. Like is he cheating? Or am i just over reacting?