Agüita'o is a colloquial term, a shortened form of agüitado, which means 'down', 'sad', or 'bummed out'. It's a less common, more informal way to express sadness or being disheartened, making it interesting for learners.
In the song, Junior H sings, "No ando enamorado, mucho menos agüita'o" (I'm not in love, much less bummed out). This phrase highlights the protagonist's detached state, emphasizing that he's not only free from romantic entanglements but also from the emotional lows that often accompany them, preferring to stay in his dream-like escape.
Junior H kicks this song off by telling us he's stuck in a dream: "Estoy atrapado / En un sueño, un sueño muy raro" (I'm trapped / In a dream, a very strange dream). But this isn't a nightmare. In fact, he loves it there. It's a place where he feels safe because there's no one around to hurt him. He wants to stay flying "Lejos, lejos de la realidad" (Far, far from reality) and never wake up.
Why does he want to escape so badly? He gives a pretty blunt reason: heartbreak. He sings that women have damaged his heart and that "Las mujeres ya no aman / Solo buscan la lana" (Women don't love anymore / They only look for money). As a result, he'd rather stay in his dream world, alone and free from anyone telling him what to do. It's his personal paradise, a safe space built to keep the real world out.