If it's sunny, I'm stuck in a cloudy day. What do you mean?

It means in a bad mood, very depressed.

Specifically, the weather can be divided into sunny and cloudy days, and your mood is like cloudy days, which means that you are in a bad mood and depressed.

Metaphor is a common rhetorical device. It is a figure of speech to describe or explain things A with things B similar to things A, also known as "metaphor" and "analogy", which was called "bi" or "bi" in ancient China. Jonathan kalle, a famous literary theorist, defines metaphor as a basic cognitive way, which is realized by treating one thing as another. That is to say, finding the * * * similarity between things A and B, we find that things A contain unknown characteristics in things B, and we have a new understanding of things A that is different from usual.