Matthew Ricks's poem is only three short lines, but it captures a feeling almost everyone knows. The speaker has done what you're supposed to do: eight hours of sleep, plus a nap on top of that. By any sensible logic, they should be rested. Yet they're sleepy anyway, and the poem ends on a plain, slightly baffled question: "Why am I sleepy?"
What the speaker feels is confusion more than distress. There's a hint of mild frustration, too, as if the body has broken a deal. The tone is flat and conversational, with no dramatic language, which makes the question sound honest and a little funny.
The mood is light, dry and relatable. Because the poem gives no answer, we're left to wonder. Maybe the speaker is simply worn out, or maybe the tiredness comes from something sleep can't fix. The poem doesn't say, and that open ending is part of its charm.