Thank you all for reading.
Yes, Kyla, "depleting" was in part an attempt to be as unromantic as possible. I'd played with words like "burning", which would certainly sound more poetic, and which would also be accurate. But I wanted to emphasize the lack of permanence and solidity, if that makes sense, and the fact that even now the sun is undergoing its inevitable process of petering out and taking earth with it. In the first stanza, I'd tried to leave in a bit of a pretty, innocent, childish way of seeing the sky; I wanted to remove that in the second stanza to indicate the increasing sense of disillusionment that came with adulthood.
I'll think about whether there's a less clumsy way to accomplish that. I'm not 100% there with this poem, I admit. (I rarely am, alas.)
ETA:
And Westie -- yes, I was trying for a bit of lullaby/nursery lilt in the meter.