The speaker describes a loneliness so complete that the weather seems to have moved inside. Rain and "I" share "one lone body," which suggests a person who feels soaked in sadness, with no one else to turn to. The questions that follow are odd and a little defiant: how do sober men cry, or dress in black? The speaker seems to be watching a performance of mourning and wondering what is real in it.
The black coat "like a hole" is a striking image. It makes the figure look less like a person than an absence, while the "hands in wild motion" hint at restlessness or distress beneath the stillness. Fasting and "playing at death" are called fashionable, which sounds slightly mocking, as if gloom has become a style. Yet the last line turns softer and more vulnerable. Being "too thin to think" of tomorrow suggests exhaustion and emptiness. The mood is dark, wry, and weary, with a theatrical edge that doesn't hide real fragility.