My (25f) fiancee (27m) started fighting with me because I didn't bring prams when we went out for a dinner.

We've been together for a year now, and I'm planning to marry him. We have a son together (4 months old). He has two children from his previous relationship that lives with us. My late night work shifts have started and I came home at 5am today. I was not in the state to be awake, and I went to sleep immediately. <br><br>My SIL called me at 9am and asked me if I could bring my BIL and the kids over for dinner as they have cancelled her BOIL's plan and are now at her home (She doesn't like them). I was half asleep and said okay without even realising what I'm saying because I was in deep sleep. <br><br>When I realised I need to bring my SIL BIL and the kids over for dinner, I was in panic. The baby wasn't sleeping much during the night and was only fed and napped for an hour. I woke her up, fed and bathed her and when I'm ready to leave the house with the kids and BIL, I realised that I forgot to pack nappies, prams, milk, bottles etc. I turned the car on and I headed over to my SILs home. When I arrived, he started arguing with me and said that I cannot bring the stroller and that it's his house (true), I can't bring the car in the house and place the pram inside (true), that I'm bringing too much stuff (true), I shouldn't have agreed to come over because I don't have time (true), I should've slept a few more hours... And the argument just went on and on. I understood that he's tired and could have given me more support, but the way in which he spoke to me was so disrespectfull and was not addressing any of my concerns. I tried to tell him that I could've been more prepared, but the baby was sick and I didn't have time to pack anything.<br><br>I don't know how to approach this discussion with him without getting him angry again. I'm not sure if I should talk to him at this stage when he's so tired, or let him sleep and then approach him.<br><br>UPDATE:<br>I would like to thank for all the helpful comments, but I can't reply to everyone because I don't have time to do so. I'm still waiting for him to wake up, apologize to me and my son for his behaviour, and talk about everything that happened today. <br><br>He asked my SIL to drop of his pants, socks, boxers and shirt to my place so I can bring them over. <br><br>The reason for his behaviour was that he didn't have time to shower, get dressed and go to work before the kids arrived. Also, he was talking to his dad on the phone at the same time and got very stressed. His stress was taking out on me and the baby. He did tell my SIL that he didn't mean to take his stress out on me, but on her as she's the one who told him that I would be bringing over all this stuff. <br><br>I've talked to him about how hurtful his words were and he apologised again.