Blackjack, where you must know when to stop, is read as judging limits. The dream may reflect a waking choice between pushing on and holding what you already have.
Does the traditional reading fit your dream, or did it mean something else to you?
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.