Yesterday, Today n Tomorrow

Life is just like we are in a cycle...we will keep loopin'..sometimes we'll be on top..
sometimes we'll be way down below....just keep remind ourself about what we should do, shouldnt do...
Since yesterday, i kept playin this song...it reminds me of sumone...
He set this song as a ring tone for me...daaa~~~
The question is : IS IT TRUE, AS WHAT THE LYRIC MEANS?