The first stanza is almost identical to the last. The only distinction between them, however, is important. In the first stanza, the speaker is:

far from you my sorrow

When we reach the final line of the closing stanza, the speaker is:

very far from you my sorrow.

That the opening and closing stanzas are almost identical would seem to suggest a cyclical nature to the poet’s emotions – he keeps on returning to her (and is perhaps fixated by her.) When the speaker concludes that he is even further away from the girl at the end of the poem than the start, the sense of pessimism is further consolidated. The journey that MacLean describes during the poem is not bringing him closer to the woman, but taking them further apart.