Is MIL wrong?

Hello. So my mother in law is helping me with my 5 week old son. And I'm very appreciative and so far it's been good. Yesterday my son was supposed to eat at 2pm but he slept all the way until 3pm and I was ecstatic that he is starting to stretch out his feedings to four hours apart. So she asks me if we should wake him up to eat and I'm like no but we have to change his diaper and that'll wake him up. She goes no problem I'll change him. So she removes him from the bouncer, takes off his blanket, takes off his clothes and of course the poor things starts to cry because now he's cold. So my MIL says to my baby: this is all your fault, your the problem here, you were supposed to eat an hour ago and that's why your so hungry and you can't blame mommy you can only blame yourself. I was completely appalled. The baby is crying because he is cold and he's an infant he isn't at fault for anything. Am I overreacting? It made me really mad.