Being an only child is read as independence and solitude, with full attention and full expectation. Dream books link it to self-reliance and the longing for company.
When this appeared in your dream, what were you feeling?
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.