Dave Bonta's "Jet lag" is only four short lines, but they capture a very specific kind of exhaustion. The speaker seems to be up in the air, on a long flight or just after one, where the usual line between day and night has dissolved. "All-day night" is a neat contradiction: it's dark, but it never ends, or the hours of darkness and daylight have blurred together so that time no longer makes sense.
The second pair of lines turns to the body. The odd phrase "upper-weary bed" makes the speaker's tiredness seem built into the place itself, as if the bed were as worn out as the person in it. "Upper" could point to altitude, a bed high above the ground, though that's an inference from the title and the first line. The broken line endings, with hyphens left hanging, mimic a mind that can't quite finish a thought. The mood is drowsy, disoriented, and quietly dreamlike, with a restless feeling of being stuck between places and between sleep and waking.