Competing with a brother or sister is read as wanting a fair share of love, attention or success. Dream books see it as comparison that still stings, at home or anywhere else.
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.