Ahogándome is a dramatic verb that means "drowning myself". It comes from the verb ahogar (to drown) combined with the reflexive pronoun me.
In this iconic song, Shakira uses this word metaphorically to express overwhelming sadness. She sings about ahogándome entre fotos y cuadernos (drowning myself among photos and notebooks), creating a powerful image of being completely submerged and suffocated by memories of a past love.
Colombian pop star Shakira goes full drama in "Estoy Aquí" (I'm Here), and it is fantastic. The track hits you with the messy reality of regret right from the start. She knows her ex is not coming back, admitting "Sé que te dejé escapar" (I know I let you get away), yet she spends the whole track trying impossible things to fix it, like wanting to turn countryside into cities and mix the sky with the ocean ("queriendo convertir / Los campos en ciudad / Mezclando el cielo con el mar"). It is completely over-the-top, but that is the point: she feels utterly helpless.
Instead of moving on, she is stuck in her room surrounded by old stuff, literally singing "Ahogándome entre fotos y cuadernos" (Drowning among photos and notebooks) and hoarding unsent letters. She even describes her spiraling state with the wild, funny line "Cambiándome un pie por la cara mía" (Swapping my foot for my face), meaning she is so confused and turned around that she cannot tell top from bottom anymore. If you have ever stayed up late obsessing over past mistakes while flipping night into day, Shakira is right there with you.