Three small observations sit side by side here: frost outside, a pain in the speaker's body, and the tired face of his wife. The title, "Morning after," hints that something has happened the night before, but the poem never says what. We are left to guess, and that gap is part of what makes it feel so uneasy.
The speaker doesn't explain his feelings. He simply lists what he notices, and the plain listing says a lot. The frost suggests chill and stillness. The bladder pain is private and a little undignified, a bodily discomfort that pulls him inward. Then comes the wife's "drawn face," which shifts the focus to someone else's weariness or strain. The line break after "drawn" makes the word linger, as if the face has been pulled tight.
The mood is subdued, tender and slightly anxious. Nothing is resolved. Judging by the details, the speaker is aware of his own discomfort but is even more struck by the look on his wife's face.