The phrase ‘my heart sank’ is an example of a metaphor.
In this expression, the speaker is not literally suggesting that their heart has physically sunk, but rather conveying a feeling of deep disappointment or sadness. This figurative language helps to evoke an emotional response, allowing the reader or listener to understand the intensity of the feeling being described.
Metaphors compare one thing to another to create a vivid image or convey a deeper meaning, and in this case, the sinking of the heart symbolizes the weight of negative emotions experienced by the person. It’s a powerful way to illustrate feelings that might otherwise be difficult to express.