Perdiste comes from the verb perder (to lose). In the context of a relationship, the phrase "me perdiste" is a powerful and final declaration meaning "you lost me."
In the song, Kali Uchis repeats this phrase to emphasize that the break-up is irreversible. It's not just that the relationship is over; it's that the other person's actions have caused them to lose her forever, capturing the song's entire mood of empowered finality.
This song is the ultimate breakup anthem for when you know you've made the right decision, even if it still hurts a little. Kali Uchis is telling her ex, in no uncertain terms, that it's over. She's almost taunting them, singing, "Me perdiste / Baby, qué triste / Tiene que doler" (You lost me / Baby, how sad / It has to hurt). She imagines them waking up alone, trying and failing to replace her, and makes it clear she's not picking up the phone if they call.
What makes the song so good is that she admits it's not easy. She acknowledges they had a real connection, saying, "You know that I got a soft spot / For you" and that "Nobody can push my buttons / Like you". She even confesses, "A veces sí me da pesar" (Sometimes I do feel regret). But despite that lingering feeling, she's standing firm. The final word is "No voy a volver / Pa nada y nunca, baby, ya me perdiste" (I'm not coming back / For anything and never, baby, you've already lost me). It's a powerful declaration of choosing yourself, even when a part of you misses what you're leaving behind.