This sleep of mine, whatever sleep it is. Were he not gone, The woodchuck could say whether it's like his Long sleep, as I describe its coming on,
These lines are incredibly romantic because Frost wonders what kind of sleep he's falling into and whether its more than just "sleep". He doesn't know if it'll be normal or death. He also compares himself to a woodchuck which are animals that hibernate just like the "long sleep" Frost describes which is almost like them "dying" and coming back when it's spring.