Nut straight against a 2-flush board

[se2schul]

On the turn I had the nut straight and had the possibility of improving to the nut straight. Did I play this wrong when there was a 2 flush on the board at the turn?

Party Poker (10 handed) converter (http://www.selachian.com/tools/bisonconverter/hhconverter.cgi)

Preflop: Hero is BB with T/images/graemlins/club.gif, A/images/graemlins/heart.gif, Q/images/graemlins/heart.gif, J/images/graemlins/diamond.gif.
<font color="#666666">3 folds</font>, Hero checks.

Flop: 6/images/graemlins/spade.gif, J/images/graemlins/club.gif, 9/images/graemlins/diamond.gif <font color="#0000FF">(7 players)</font>
Hero bets [$0.25].
5 calls

Turn: K/images/graemlins/spade.gif <font color="#0000FF">(6 players)</font>
UTG+1 folds, UTG+2 folds, Button folds.
Hero bets [$3.10].
1 calls [$3.10].
2 folds.
1 raises [$9].
1 folds.
Hero is all-In [$18.69]
someone else all-In [$18.55]
another person calls [$12.79].

River: 2/images/graemlins/spade.gif <font color="#0000FF">(3 players)</font>

Final Pot:

[graarrg]

My instinct says to do the same to protect the hand from the flush draw, but you have to consider that there was a raise ahead of you, which likely means the same straight.

Now, since you have a redraw, either you're freerolling him or he's freerolling you if he has the flush draw. But if you include your other opponents (Who would be willing to call with a lone flush draw), it's not worth playing for half of this pot.

I'm a little indecisive, but you can at least be sure that you had to either fold or push.