Seeing things that are not there, even inside a dream, is read as doubt about what is real. Dream books link it to mixed signals in waking life and to the need to check what you are told against what you know.
Where in your waking life have you met something like this lately?
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.