Deleting something is read as letting go, removing what no longer belongs in your life. Regretting a deletion in a dream is traditionally taken as fear of losing what cannot be recovered.
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.