There's this song i listen to repeatedly all day?

Question

but it's a really sad song... is that why i'm so depressed lately??

could a song affect my mood so much?

Answer 1

If you're depressed, you could be more prone to listen to sad songs.  Conversely, music can change your mood.  Try listening to something with a little more of a positive outlook.

Answer 2

Oh my goodness, yes.   I find myself affected more by the music itself, though, rather than the lyrics.

If you are susceptible, why not put on something cheery?

Answer 3

if the lyrics are powerful enough to you, then definitely yes, this could be the reason you are depressed.