She most likely does know there's going to be a big change. I'm sure J knew. But it's also around the age that the terrible twos started with T, so it could be that too. Or a combination of both. Unfortunately there's not much you can do about it, terrible twos will happen, but if you are able to handle it patiently and use it to help her learn it will stand her in good stead. But don't be too hard on yourself if you lose atience, we are all human and when pg and when you have a nb and toddler, it is really, really tough.

I hope that it's just a short phase for you.