Walking in My Shadow

Contest poem. :)

For years,
I always felt that,
Someone has been walking,
In my shadows,
I don't know who,
But I know there is someone,
I feel them,
Walking in my shadow,
Copying my every move,
Copying my every words,
I feel them,
Creeping up on me,
In my window at night,
Watching my chest rise,
And fall as I sleep,
I can feel someone,
Walking in my shadow,
But I don't know who,
I guess,
It could be my imagination playing tricks on me.