This one is pure heartbreak with no pretending. Someone the singer lost asks how she's doing, and she decides to be honest: "Se quer a verdade, ainda tô sofrendo" (If you want the truth, I'm still suffering). She's "pela metade" (half of myself, only half there), her heart aching, and "o tempo não tá melhorando essa dor" (time isn't making this pain any better). So much for time healing everything.
She also admits "Eu sei porque eu te perdi" (I know why I lost you), so she isn't blaming anyone but herself. The bridge is the most human part: "Eu tento me enganar, mas me conheço tão bem" (I try to fool myself, but I know myself too well). Learner tip: tô and tá are the spoken short forms of estou and está, and you'll hear them in almost every Brazilian song.