The poem begins like a cheerful morning: sunshine, a good breakfast, smiling strangers, glittering light. But the speaker already feels "cool" and in a hurry, and the hint is easy to miss until the end. The "best friend" they rush to turns out to be heroin, the drug that takes away pain and replaces it with "endless bliss."
The mood shifts from bright and hopeful to anxious and hollow. The speaker is exhausted by the "quick change between happiness and pain," which they call "heaven and hell." Relief depends on money, so every tomorrow brings fear: what if they can't pay, and what will the "friend" do then? The tone is quiet and almost matter-of-fact, which makes it more unsettling.
The last lines are the saddest. The speaker hopes there will soon be "no more tomorrow," suggesting they see release only in an end to everything. Calling the drug a friend shows how dependence can feel like comfort while it traps the person completely.