How much sadness can you have? It's just a river flowing eastward. What kind of feelings did the poet express?

This sentence comes from the poet Li Yu's When is the Spring Flower and Autumn Moon? . It expresses the poet's deep sorrow and sadness, like a spring, which keeps flowing eastward and can't stop.

The poet uses the question "How much sadness can you have" to express his inner pain and helplessness. He seems to be asking himself how deep, how thick and how unbearable this sadness is. Then, he used the metaphor of "just a river flowing eastward" to vividly describe the sadness and sadness in his heart. This kind of sadness and sadness, like a river flowing eastward, can't stop.

The whole poem expresses the poet's deep feelings of loneliness, pain and helplessness, and it is vividly portrayed in the poet's pen, which makes people moved.