'I'm Down' by The Beatles is an energetic rock song revolving around the theme of romantic frustration and the emotional turmoil that comes with it. The song's narrator expresses deep feelings of being let down and heartbroken due to their significant other's actions. Key themes include love, heartbreak, and emotional distress. Noteworthy moments in the song include the raw vocal intensity by Paul McCartney, which conveys the urgency and depth of his feelings, and the repetitive chorus that emphasizes the desperate plea for understanding and emotional relief.