Analysis of The first Day's Night had come

The first Day's Night had come—
And grateful that a thing
So terrible—had been endured—
I told my Soul to sing—

She said her Strings were snapt—
Her Bow—to Atoms blown—
And so to mend her—gave me work
Until another Morn—

And then—a Day as huge
As Yesterdays in pairs,
Unrolled its horror in my face—
Until it blocked my eyes—

My Brain—begun to laugh—
I mumbled—like a fool—
And tho' 'tis Years ago—that Day—
My Brain keeps giggling—still.

And Something's odd—within—
That person that I was—
And this One—do not feel the same—
Could it be Madness—this?