You did nothing wrong. Most of the time he will not hit the straight and it will be a split pot. The only alternative is to fold preflop, or move in because any meaningful raise (if called) would have committed you to the pot anyway.

Given there was $2,000 in the pot and you only have $10,000 left moving all in preflop is not an unreasonable play (as is simply folding). However, I'd rather move in with 78 suited than A2 suited because of the likelihood of only having one live card if called.

You did the hard work by putting yourself in the situation to get lucky and qualify. Unfortunately once the blinds are so big in relation to the stacks luck plays a big part and this time it wasn't on your side.

No regrets I say.