short version: Aggressive terran has terrible macro! A lesson that managing your base is often more important than managing your attack.
You could have attacked his bunkers earlier with your immortal, though you may have thought they were full generally? Would have made things *much* easier.
Also when you attacked his base I was surprised you didn't hit his expansion a bit more. I guess you picked correctly for the kill, but seems risky -- if you'd have knocked his money production out seems like a more sure thing over a longer game. At least, to me it does. But I suck.