She was excited??
Okay, that doesn't sound like a "I'm afraid" kind of thing... can't be sure of course, but if a kid (anyone really) was acting all happy I'd be asking myself just how much of a pushover I'd been.
Toddlers ARE known for testing every boundary they can think of... and for doing...
I'd try and figure what it is that's causing the upset... could be something as simple as a tree branch and a street light coming through the window and freaking her out... could be a nightmare... could be she heard someone else's grama died... or could be another form of separation anxiety...