The monster under the bed is read as childhood fear that never quite left. Dream books see it as a small, old anxiety that grows in the dark when it is not faced.
Does the traditional reading fit your dream, or did it mean something else to you?
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.