Re: that's what I don't get ...
If she was very irregular and often skipped a period or three, or she had spotting the whole time, I can sort of see where she could convince herself nothing strange was going on. But again, it smacks of either stupidity or deep denial. Pregnancy has such a constellation of symptoms, not least includes breast changes. And like I said, the feeling of a near-full-term baby moving around inside you cannot be mistaken for anything else. It's just not believable.
I think, therefore I judge.