What is the theme of the poem "Homesickness" and what are the poet's four feelings?

Homesickness is the feeling and yearning for hometown, and it is an emotional state of attachment to hometown. Attachment to hometown is a constant and eternal emotion of human beings. Wanderers, vagrants and floating population who are far away from home will miss home.

The first section: studying in the early years, separating mother and child, comforting each other by letters; Section 2: After adulthood, bid farewell to the newly married wife and leave home, living far apart; Section 3: Where will you go? Mother and son are not allowed to meet. Section 4: It is rare for compatriots to get together and the country cannot be unified. At the same time, readers can also feel the author's rich and strong feelings. The poet's homesickness is not directly expressed, but through association and imagination, four artistic images of life are shaped and presented to readers. The author combines his thoughts and feelings for his mother, wife and motherland, and expresses his strong desire for family reunion and national unity.