William Blake's 'AH! SUN-FLOWER', what is it about?

Hey everyone, I just stumbled across this site whilst looking for information on William Blake's poem 'Ah! Sun-flower' and was wondering what your take was on this poem. I typed it out in the event you haven't come across it.

Ah, Sun-flower, weary of time,
Who countest the steps of the Sun,
Seeking after that sweet golden clime
Where the traveller's journey is done:

Where the Youth pined away with desire,
And the pale Virgin shrouded in snow
Arise from their graves, and aspire
Where my Sun-flower wishes to go.

This is taken from 'Songs of Experience' and is one of those poems of his where I'm not too sure about what he's trying to say. When I first read it, my first reaction was: heaven. The Sun flower is weary of time and thus presumably life and the fact that virgins arising from their graves aspire to go to the same place seems to me concrete evidence that he is talking about the after life. Apart from that however, and some other minor remarks (like how this differs from 'Songs of Innocence' because the flower is tired of life rather than embracing it in joy), there's nothing I can add! For example, what does he mean with 'Youth pined away with desire'? What about the 'Virgin shrouded in snow'? Is there any symbolism beyond the purity of their soul and the obvious physical symptoms of being dead? Also, I've got to write an essay on this poem (amongst others) in which I am to explore Blake's attitude to love referring to this poem. The only reference to love I can make out is the lack of love for life. I would be very grateful for any suggestions or anything you can add! Thanks for your time!