For some reason, I feel sad when I listen to certain music; particularly music with soothing female vocals or music that has lyrics that talk about love.

Tonight, for example, I am studying and finishing up homework while listening to dark chillstep on YouTube because it helps me focus. The music has been fine, but then autoplay switched to a different artist and type of chillstep that had some soft soothing female vocals. When this song came on, I felt sadness and felt like crying.

I almost have to stop listening to certain types of music entirely because of this reason. Most of my music library is metal, aggrotech, techno, EDM, dubstep, and new age because listening to more aggressive sounding music makes me feel better than listening to softer tunes and feeling sadness or longing as a result.

Why does this happen to me?