If you read the poem carefully you can see a number of different images that the poet uses to describe how the speaker in this poem feels. Just consider the first three lines:
When I go away from you
Whe world beats dead
Like a slackened drum.
Note how this simile creates an incredibly powerful image, depicting how bereft the speaker is in her life when she leaves her beloved. The world is compared to a "slackened" drum which is beating "dead", which of course uses onomatopoeia in "beat" to enact the sound that the image creates. Note how the poem continues:
I call out for you against the jutted stars
And shout into the ridges of the wind.
Two implied metaphors are used here to further paint a picture of the bleak landscape which the speaker inhabits without her lover - the stars are made out to be high, jutted mountains that hem her in and the wind likewise has "ridges", equally creating an image of the speaker feeling imprisoned and caged by nature. Life without her love is certainly very difficult for her.