Presentía is a form of the verb presentir, meaning "to have a premonition" or "to sense" something before it happens. It's a poetic word that describes a gut feeling or intuition, often about something negative.
In this emotional ballad, the singer expresses her deep regret, singing "...yo lo presentía / Que te irías para siempre de mi lado" (...I sensed / That you would leave my side forever). This word reveals her tragic foresight, the heartbreaking intuition that she was always destined to lose her love, which makes her sorrow even more profound.
This song is a powerful story of regret. The singer tells us her life is completely stuck, or as she puts it, "Mí vida está en pausa desde que te fuiste" (My life is on pause since you left). She admits she pushed her partner away because she was afraid of getting hurt, thinking he would eventually leave her anyway. Now, she's left with overwhelming sadness, doing things like calling out his name and getting no answer, and falling asleep while "abrazada a tu ropa" (hugging your clothes).
She takes all the blame, saying "Reconozco que la culpa ha sido mía" (I recognize the fault was mine). She realizes too late how much she loved him and how much he taught her, especially that it was possible "volver a soñar cada día" (to dream again every day). The song is a confession of this huge mistake, a cry of deep regret for letting fear ruin a great love.