Oh no! William is back?

Hmmm...
Not sure what to make of today's greeting when William and I walked into the library this morning. Since we have been away, we have missed three weeks (meetings) of playtime at the library. When Miss Jane saw us coming her way, she said, "Oh no! William is back!" Granted, it was a light tone of voice. When we got into the children's library, she greeting William and said they had missed him, asking if he had a good trip. Later, she told me it was a greeting of endearment. Still, I have to wonder at the choice of words.