The next sentence of this sentence is to express my longing for you.
This poem expresses deep feelings of longing. Through the image and vivid description of "thousands of threads", it shows the intricate and complicated emotional entanglements between people, emphasizing that The deep concern and longing in people's hearts. When we are very affectionate for someone, that kind of care and longing will turn into thousands of lingering emotions, making it difficult for us to let go.
The phrase "turn into longing to express lovesickness" expresses that people transform this longing into an action, that is, thinking with their hearts and expressing their longing with actions. In this era of information explosion, in order to convey their longing to people far away, people now use various technological means, such as text messages, phone calls, emails, etc., to express their longing and care for each other.