The speaker is dealing with insomnia, and they talk about it as if sleep were a lover who has drifted away. Sleep is a "flighty temptress" who shows up briefly, offers a light touch and an "empty promise," then disappears again. Meanwhile, other people seem to enjoy her company, and the advice to try pills feels like a clumsy way to win her back. The speaker's bitterness flashes out in the blunt line calling sleep a "whore," but it sits beside real longing.
Underneath the anger, the mood is lonely and tender. The speaker remembers being young, when sleep and the self "couldn't stay away" from each other, and now waits up like someone listening for a partner to come home. The ending is quiet and resigned. The speaker says they know sleep won't return, and the poem leaves us with the tired sadness of a relationship that has already ended, even though the waiting goes on.