Sharks in dreams usually embody a primal fear -- something that feels dangerous precisely because it's silent, fast, and hard to see coming. Being chased or circled by a shark can reflect a threat you sense in a relationship or situation but haven't been able to name outright. The dream rarely points to literal danger; it's more often flagging a predatory dynamic worth looking at directly.
Always note the configurations of the stars, not by their signs, but orbs. - William Lilly (1602.-1681.)