Clarice Bean, Don't Look Now
The third book in Lauren Child's Clarice Bean series.
It's the worry you hadn't even thought to worry about that should worry you the most. At least that's how it looks to Clarice Bean, who has been writing her worries in a notebook - things like Worry no. 1: infinity, or Worry no. 3: change.
And now that her worst never-imagined worry has happened - her utterly best friend is moving away forever - Clarice doesn't even care about her tickets to the Ruby Redfort, girl detective, film premiere. That is, unless something happens to change things again...