First 5 Days of Heartbreak

[Collapsed We Swear]

Day 1:
Maybe breath is superfluous. —I think this line is superfluous. I know you're trying to get the 4 lines in, but this line is redundant. Especially for how exceptionally good the following three lines are. 
Anchored to grief, like great stones,
the lungs collapse—
loss constantly arriving. —I appreciate lack of punctuation is apparently on the cutting edge of creative expression, but personally, I'd punctuate it. The whole thing—so, I won't mention it again, but it's implied.
 
Day 2:
Sick with sewage
swallowing boiling anger
there is no room in the kettle of my stomach—"there is no room in the kettle of my stomach" is fucking brilliant. I love this line. I want to marry it and have its babies.
for perspective to crest over the burn
 
Day 3:
When the claxons ring out,—now you've started punctuating it. As if you preempted my criticism. 
tamp down the reverberation with my hands
shivers held in place by tight tendons
that pain might not rend them to rags
 
Day 4:
Who lies to the wind?
Heartbreak floats on it,
featherlight and perfumed
like love, unbothered by its endless circles
 
Day 5:
Resolution is not
serenity in the filtered sun of empty hallways
but footsteps, grinding and heavy
inching forward one hour at a time

This is a fine poem. There are moments of pure confident originality—the first couple of stanzas are excellent examples of this. 
Some of the word choices and turns of phrase are a little "boring" or sentimental—filler-ish. But on the whole it's very well written, demonstrating a good, above-foundational, grasp of language and how to manipulate it.