A2 poetry analysis help.

This is for all those appearing for their Literature exams this May, and others as well. I need help with Auden's poetry. Here's Refugee Blues by W. H. Auden.

Say this city has ten million souls,
Some are living in mansions, some are living in holes:
Yet there's no place for us, my dear, yet there's no place for us.

Once we had a country and we thought it fair,
Look in the atlas and you'll find it there:
We cannot go there now, my dear, we cannot go there now.

In the village churchyard there grows an old yew,
Every spring it blossoms anew:
Old passports can't do that, my dear, old passports can't do that.

The consul banged the table and said,
"If you've got no passport you're officially dead":
But we are still alive, my dear, but we are still alive.

Went to a committee; they offered me a chair;
Asked me politely to return next year:
But where shall we go to-day, my dear, but where shall we go to-day?

Came to a public meeting; the speaker got up and said;
"If we let them in, they will steal our daily bread":
He was talking of you and me, my dear, he was talking of you and me.

Thought I heard the thunder rumbling in the sky;
It was Hitler over Europe, saying, "They must die":
O we were in his mind, my dear, O we were in his mind.

Saw a poodle in a jacket fastened with a pin,
Saw a door opened and a cat let in:
But they weren't German Jews, my dear, but they weren't German Jews.

Went down the harbour and stood upon the quay,
Saw the fish swimming as if they were free:
Only ten feet away, my dear, only ten feet away.

Walked through a wood, saw the birds in the trees;
They had no politicians and sang at their ease:
They weren't the human race, my dear, they weren't the human race.

Dreamed I saw a building with a thousand floors,
A thousand windows and a thousand doors:
Not one of them was ours, my dear, not one of them was ours.

Stood on a great plain in the falling snow;
Ten thousand soldiers marched to and fro:
Looking for you and me, my dear, looking for you and me.

I'm almost done with it but I can't determine the tone of the poem. Is it lamenting, angry, bitter, sad? If yes, how?
Plus I'm having trouble figuring out poetic devices in the poem, for instance, there's a lot of natural imagery('old yew', 'fishes swimming', 'birds in the trees'). Then there's personification('thunder rumbling in the sky').
What else should I be looking for?

Thank you. Your help is much appreciated. :)