Nothing malfunctioned

There is a version of this where your body let you down, or your faith did, or you are simply not built for it. None of those is what happened.

Three ordinary things arrive at once after a birth, and each of them on its own would make anybody worse at managing feeling. They arrive together, in the same week, in a person who is also learning to keep a new human alive.

That is the whole mechanism. It is not mysterious and it is not a judgement. Read the three, and then look at the loop they make.