Being left alone is read as fear of loss and of not being enough to stay for. Dream books also see it as a part of you that feels neglected and wants your own attention.
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.