Nice comeback. I bet your opponent didn't realize how much trouble his own king could get in! I think 36...h5 was bad, probably 36...Rb3 would have stopped your plan, for example 37 Rxa5 Rxc3 38 Ra6 Kf7 39 Kh5?? Rh3#. Still, you really punished him for that move and his lazy play.
Here's a Bird game where I came back from a rook and pawn endgame down 2 pawns!