Clavado literally means "nailed" or "stuck". However, in Mexican slang, it's often used to describe being deeply infatuated or "hooked" on someone.
In this song, the lyric "Pues ya estaba bien clavado" perfectly captures the feeling of being completely smitten and emotionally invested in someone, making the breakup even more painful. It's a vivid and relatable expression of intense romantic attachment.
Have you ever been completely blindsided by a breakup? That's exactly what Los Plebes del Rancho de Ariel Camacho are singing about in "En Un Día Como Hoy." The singer is still reeling from the moment his ex told him she didn't want to be part of his life anymore, and that she didn't feel anything for him. He really thought he had her in love, but it turns out there was someone else in her heart. Ouch!
He remembers the exact day it happened: "En un día como hoy, a media tarde y el cielo nublado" [On a day like today, in the afternoon and the sky cloudy]. For him, the world ended right then. He was totally "clavado" [hooked] on her, and she just left without a trace. He can't believe she didn't realize how important she was to him, saying, "La tuve contemplada entre mis prioridades ¿Qué acaso no se dio cuenta?" [I had her among my priorities, didn't she realize?]. It's a tough song about the pain of a sudden, unexpected heartbreak and how hard it is to live without that person.