Perhaps the thing to remember is that it's all writing.

Outlining is writing. Mulling plot points while you wander campus is writing. Having a conversation with your characters over breakfast is writing. Reading other people's books is writing (no, really). And yes, even sitting in classes on nonwriting subjects is writing because there's no such thing as nonwriting subjects!.

You are a writer. You are an organic machine designed to take all the world's input and perform a miraculous blackbox function upon it and then extrude finished prose.

Scary, huh?