The very first day I saw you, my love, I fell in love with you. You haven't left my mind ever since. Please, come back to me. Frank.
Remarks about the translation
I imagine that "mind" is what he meant. It could also be "sight" but in this case it would mean that the writer is "watching" the other person all the time.
Foi o que eu tratei de esclarecer na nota : a palavra certa seria "sight" mas...não darÃa a entender que há um tipo de "vigilância" sobre a coitada? hahaha
Neste caso acho que "mind" resolve.
Existem várias expressões que ilustram bem o pensamento do texto, como:
You are always in my mind.
Can't take you out of my mind.