Ive been in this situation a lot, and you probably know this already. IMO I dont think I would have pushed post flop...I would have made a decent sized bet to see how he reacts. Ive been getting killed like this lately..Raise preflop and they end up getting the str8 like this with K6o and such.

If it makes you feel any better I lost late in a tourney i played today with AA to KJo. I raised half my stackpreflop trying to pick up the pot from 5 limpers. Got reraised all in by the guy with KJ. What happens? He ends up getting a flush with 4d's on the board. Like its susposed to make you feel better when they say sorry...HA HA...*sniff.