Sounds like your milk could be in to me too. With DS2 it just kind of happened, there was no moment where my BB's when rock-hard, I just noticed that he had milk spilling out the side of his mouth.

Can you hand express a little bit to see it it's white like milk?

ETA - As for feeding 2 hourly once your milk comes in, I haven't heard of that! I would feed DS#2 2 1/2 - 3 hourly throughout the day (unless he was hungry earlier) and he breastfed fantastically!