Unlike some other passages, this one didn’t come to me quickly, but as I though more deeply into the meaning of the passage, I heard the song ringing in my head. I believe the lines “My mind has been dragged down so far, Lesbia, thanks to you, and squandered itself so much in its devotion” show that Lesbia has left, and his efforts have been in vane. Which is reflected when The Doors sing “Don’t you love her madly? Wanna be her daddy? Don’t ya love her face? Don’t ya love her as she’s walkin’ out the door” which shows the love for the woman in the song, even as she’s leaving him, which is also how Catullus feels. However, where it becomes interesting is when Catullus says, “that it could no longer love you, even if you were perfect, or stop wanting you, no matter what you did.” I believe this is Catullus going between “Loving her madly” and being indifferent to her not being there for him. The similarity is that he could not stop wanting her, even though she has caused his mind to squander itself over loving her madly.
The other interesting passage from the song are the lines “All your love is gone So sing a lonely song Of a deep blue dream Seven horses seem to be on the mark.” The seven horses is most likely a reference to the biblical story of the apocalypse, which is a day of reckoning as she walks out the door, and at the same time Catullus is reckoning with how Lesbia has caused him such turmoil in his life.
(Catullus 75)
My mind has been dragged down so far, Lesbia, thanks to you,
and squandered itself so much in its devotion,
that it could no longer love you, even if you were perfect,
or stop wanting you, no matter what you did.