Amanecida is a nuanced Spanish word used as a noun to describe an 'all-nighter' or 'a night spent awake until sunrise'. It comes from the beautiful verb amanecer, which means 'to dawn'.
In the song, the narrator describes his cycle of self-destruction, singing "Otra amanecida, y esta cruda maldita me va a enloquecer" (Another all-nighter, and this damned hangover is going to drive me crazy). The word perfectly captures the feeling of a long night of partying and regret bleeding into the morning.
This song is a brutally honest breakup story from the guy who knows he messed up. Neton Vega isn't making excuses; he lays it all out. He admits, "Yo no soy romántico, pero contigo, neta, la cagué" (I'm not romantic, but with you, honestly, I messed up). While his ex wanted a "puta luna de miel" (damn honeymoon), he was too busy being wild and never gave her flowers or serenades. The final straw? He came home "oliendo a otra piel" (smelling of another woman's skin).
Now he's dealing with the aftermath. He's stuck in a cycle of drunken nights and hangovers, making calls she won't answer. He knows they were a bad match, singing, "Tú bajaste del cielo, y pa' allá nunca iré" (You came down from heaven, and I'll never go there). But even though he admits fault, he's also incredibly confident. He sees her with someone new and thinks, "Puedes reemplazarme, pero no olvidarme" (You can replace me, but you can't forget me). It's a mix of regret and pure ego.