Should I be upset? Would you be upset?

My boyfriend works double shift 4 days, Thursday-Sun. We saw each other once Thursday to sleep togethor a couple of hours + have sex. Well since then he's been working and he's busy I get that. What I don't get is he doesn't reply to my msg at all. We don't have each other on any social media because it causes arguments so we only speak through regular texts and whatsapp. During work he's constantly getting on whatsapp so that means he does have moments of time to reply to his friends or whoever he is speaking to. Just doesn't have time to reply to me. Today he sent his msg to me at 3 PM!!! He's been awake since 10 am and constantly getting on but doesn't write to me until he feels like it. That was his first and last msg to me today. Got on the rest of the day just didn't have time to even open my msg but friends msg yeah. Am I overreacting? I spoke to him about this before and nothing changes. He thinks it's OK doesn't see anything wrong with it but I do. He and I do not live togethor and have different schedules so we mostly communicate through msg until we see each other.

Would you get mad if your was working but only sent you ONE msg the whole day (saying "hey how are you?") Got online the rest of the day during work and didnt reply to you???