Re: Weaning & Hormones?
It's an interesting question, and I did some poking around on Google Scholar looking for articles addressing this phenomenon, but didn't find anything relevant. Since post-weaning nausea unrelated to pregnancy seems to be uncommon, and not particularly debilitating, I suspect that no-one has ever taken a particularly close look at it.
I think your hypothesis that this is all a matter of your hormones rebalancing themselves as prolactin production drops is a good one. I know that my first postpartum cycles have been more whacko (for lack of a better word) than average- the ups are more intense, the lows are worse, and my period itself... Yuck.
But on the other hand, it seems like the potential for this to be some sort of nasty tummy bug is there, too. I know you feel like you ruled it out, but the progression from nausea to diarrhea is kind of classic tummy bug. Just sayin'.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"