Yes, it's a regular feature of the Nancy Drew games, isn't it? I find there are two times that happens to me -- when there's a puzzle I either can't or don't want to solve that I've been ignoring, or when there was some tiny and trivial little thing the game assumed I would do early on that I somehow didn't do. Here are some ways I've found of getting things going again.
Call everyone, talk to everyone, visit every scene again. They might have something new to say; you never know.
When you talk to someone, click on every conversation option. Don't be too quick to hit the "fast convo" button; you'll miss a lot of important details, and Nancy doesn't write everything in her journal.
Read through Nancy's journal to see what puzzles you might have forgotten about. This game has a lot of puzzles that you discover early but can't solve till the end of the game, so it's easy to forget they're there.
That said, it's also a good idea to keep your own physical notes in the real world. There are a couple of important things in this game, passwords and suchlike, that Nancy doesn't record in her journal.
Follow the Jabberwocky poem your Mom gave you. If you got your luggage back, open it; after Nancy comments, call Ned to see if he can get one for you from your home.