When I listened to Past Masters, Volume 1 yester-day, I noticed a couple things about "I'm Down."
The "every" in the second verse ("Man buys ring; woman throws it away / Same old thing happen every day") is sung with three syllables, giving a sense of number or frequency.
The backing vocals in the chorus ("I'm really down / Down on the ground / I'm really down") are sung to (generally) descending phrases that musically reflect that "down." There are two parts there, something like: