The speaker is caught in a night of heavy longing. The poem opens with a kind of grim comfort: "Sooner or later, it's over." It could mean the pain will pass, or that whatever they shared will end, and the poem leaves that open. What the speaker wants is oddly specific. They don't want to miss the person tonight, and by the end that wish hardens into "I cant afford to miss you."
The feelings are physical as well as mental. The mind is "swarming" with horrible thoughts, and the body is trembling from sadness. Both suggest someone overwhelmed and unable to settle. The title, "Intensity," and the subtitle, "the great flood," fit this, since the emotion seems to arrive in a rush that can't be held back.
The mood is raw and anxious, and the short, repeated lines make it feel like a plea. The small typos even add to the sense of someone writing in a hurry, in the middle of the feeling.