It was already painful the first time - perhaps it is that she never expected it to happen again, chose to believe that was the whole story and the end, that it is so much harder the second time.

"Go back to your home," she is told, and hears "go back to being a child" but she hasn't been a child since she landed in Narnia the first time, and how is that fair at all, how is she supposed to go back to being something she hasn't been in an uncountable number of years?

Well, she's always been good at out playing other people's games.