Sarah's "destruction" is only three lines long, but it holds a surprising idea: that feeling nothing and feeling everything can both be painful. The speaker describes most days as numb, a flat, muted state where emotions don't quite reach them. Then come the rare days when everything switches on at once, and you might expect that to feel like relief.
Instead, the last line turns it around. Those are the days that "destroy you." The word "somehow" suggests the speaker doesn't fully understand why. It's almost a shrug of confusion, as if they wish the answer were simpler.
The mood is quiet, tired, and a little resigned. The lowercase title and plain wording make it feel like a private thought rather than a polished statement. Numbness may be dull, but it protects. Feeling everything leaves the speaker with no defense, and the poem lets that hang there without offering comfort.