Flopped flush again - how did I blow it this time?

No reads on players.
Oh My God, how did I screw this up?!?!

PokerStars 3/6 Hold'em (6 handed) FTR converter on zerodivide.cx

Preflop: Hero is SB with 5[img]/images/graemlins/heart.gif[/img], Q[img]/images/graemlins/heart.gif[/img].
UTG calls, MP calls, CO calls, <font color="#666666">1 fold</font>, Hero completes, BB checks.

Flop: (5 SB) 7[img]/images/graemlins/heart.gif[/img], 6[img]/images/graemlins/heart.gif[/img], 2[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(5 players)</font>
Hero checks, <font color="#CC3333">BB bets</font>, UTG calls, <font color="#CC3333">MP raises</font>, CO calls, <font color="#CC3333">Hero 3-bets</font>, BB calls, UTG folds, MP calls, CO calls.

Turn: (9 BB) 6[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(4 players)</font>
<font color="#CC3333">Hero bets</font>, BB calls, MP calls, CO calls.

River: (13 BB) 2[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(4 players)</font>
<font color="#CC3333">Hero bets</font>, BB calls, MP calls, <font color="#CC3333">CO raises</font>, Hero calls, BB calls, MP calls.

Final Pot: 21 BB
<font color="#009B00">Main Pot: 21 BB, between MP, CO, Hero and BB.</font>

[TheKentock]

well, you screwed it up when you let the board double-pair.

Don't do that next time, you're golden.