Is it a love poem

This sounds like a love poem. Not just because the writer repeatedly saying "I love you" but throughout the whole poem, it describes how everything change because the writer loves his/her mate. I don't understand your last question. What do you mean by "Can I face it as the mother's love poem?"

2011-08-07 10:46:23 補充：
I believe you are asking "is it a poem expressing mother's love?"

My answer to this question would be no. Just simply have a look at the last sentence. The writer said "Crazy with joy because I love you" Normally mother's love would not be described with crazy but with warmth and happiness.

2011-08-07 10:49:29 補充：
Throughout the whole poem, it more looks like a poem between a young couple more than the love between parents and child.

Also, the atmosphere of the poem is quite positive. At least in the writer's side. Have a look at the 6th and 7th line

2011-08-07 10:50:46 補充：
And takes no heed of the moon dragging it away
And saying coldly 'Constancy is not for you'.

I don't think mothers will normally say to their kids "Constancy is not for you" . If that mother says so, the writer would not have written the poem in this way

I think this poem expresses the love given by the nature or the god.

Is it a mother's love poem? ?

ans: I don't think so.