Trágame comes from the verb tragar (to swallow). It's part of the dramatic Spanish idiom ¡Trágame tierra!, which literally translates to "Earth, swallow me!"
This powerful phrase is used to express an overwhelming desire to disappear from a situation, often due to extreme embarrassment or, in this case, unbearable heartbreak. In the song, Selena cries out "Mátame cielo, trágame tierra" (Kill me, heaven; swallow me, earth), conveying the absolute depth of her despair over a lost love. It's a poetic and intensely emotional expression you won't find in many songs.
This song is pure, unfiltered heartbreak. The singer's heart is still in love, but it's also "muriendo, tarde con tarde" (dying, afternoon by afternoon). She begs her lost love to come back, calling them "alma de mi alma, vidita mía" (soul of my soul, my little life). It gets incredibly dramatic when she says she wants the heavens to kill her and the earth to swallow her up—"Quiero morirme / Si no vuelve más" (I want to die / If you don't come back). It's a lot, but it's exactly how this kind of pain can feel.
Then, the song takes a turn. The singer imagines her ex having everything: "el mundo entero" (the whole world), a new love, and total happiness. But she leaves them with a chilling warning. She predicts that one day, they too will find themselves alone, just like she is now. And when that day comes, they will finally understand that without true love, "Siempre hace frío" (It's always cold).