Hypersomnia means sleeping far too much, and the poem puts that experience into a few spare lines. It opens with a clock that has "a looseness" at "several times," as if the hours no longer hold their shape. Time has gone slack, and the speaker can't trust it to mark out a normal day.
The second stanza gives a reason. The speaker fears "day's fire," which suggests that waking life feels too bright, hot, or demanding. So they "call for ash," asking for something burnt out and quiet instead. Sleep arrives as a kind of cover, and the last lines say it "papers over" the morning, like wallpaper hiding a crack or a blank sheet laid across something unpleasant.
The mood is muted and a little numb. The speaker doesn't shout or complain; they simply describe retreating. The short lines and lack of punctuation make it feel drowsy, and also slightly worrying, since the escape comes at the cost of the day itself.