The size of the whale is mostly related to the dreamer's personal sense of smallness or personal repressed feelings, and the boundless sea often symbolizes a complex emotional world;
Sharks belong to marine animals and usually indicate problems in the emotional field. Sharks are often associated with people's subconscious, symbolizing the fear of death. Dreaming of sharks means that the dreamer has been unfairly violated, or someone wants to seize the power that belongs to the dreamer.
Have you been under a lot of pressure recently? Talk to reliable relatives and friends, and you may get good advice!