The speaker feels unseen, as if they are slowly vanishing from the life of someone who once mattered to them. The title, "Mist," fits that feeling well: mist is faint, hard to hold, and gradually thins until nothing is left. The speaker isn't describing a sudden break but a quiet drifting away, and the word "slowly" makes it sound almost painful to watch.
The lines move from "invisible" to "falling" to being someone "you'll hear about" rather than someone you know. In other words, the speaker is becoming a distant name, then perhaps not even that. The trailing dots suggest hesitation, as though the thoughts keep fading before they finish. The last line shifts from loneliness to something bigger: being overlooked is so hurtful that the speaker starts doubting they matter at all. The mood is sad, tender, and exposed, like a confession made quietly because no one seems to be listening.