A notebook stands for private thoughts and memory, a place for what you want to keep. Blank pages are read as potential; lost notes as fear of forgetting something important.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.