The melody of I’m a Mess by Ed Sheeran runs 478 notes across 75 bars, 3:58 long in Fm at 140 beats per minute. The tab sits almost entirely in the first two frets, one note at a time — no chords to barre and no strumming pattern to keep up with. A piano backing track plays the chords and bass underneath, so the line you are learning sounds like the record even at half speed.
Prefer to strum and sing it instead? I’m a Mess chords and lyrics.