I mean. There is this condition that I don't remember the name of where people look perpetually pregnant, so I don't assume. Also, some people just don't show much even very late. Plus, as you say, it is winter.

I think you're in the clear in general although if you had fed the dog before you might have noticed the carrier. XD Though I wonder why she didn't take it with her since, eventually, she will need to transport that baby home. A mystery.