Flopped straight, raised on turn w/3rd flush card

[LowDown22]

At the time of this hand I have only had 7 hands with the CO, but he seems very loose preflop and fairly passive postflop. Haven't seen him do anything crazy postflop.

Party Poker 2/4 Hold'em (10 handed) converter

Preflop: Hero is UTG+1 with Q[img]/images/graemlins/diamond.gif[/img], J[img]/images/graemlins/diamond.gif[/img].
Hero calls, <font color="#666666">2 folds</font>, <font color="#CC3333">MP2 raises</font>, <font color="#666666">1 fold</font>, CO calls, Button calls, SB calls, BB calls, Hero calls.

Flop: (12 SB) T[img]/images/graemlins/spade.gif[/img], 8[img]/images/graemlins/club.gif[/img], 9[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(7 players)</font>
SB checks, BB checks, <font color="#CC3333">Hero bets</font>, MP2 calls, CO calls, Button folds, SB calls, BB folds.

Turn: (8 BB) 6[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(5 players)</font>
SB checks, <font color="#CC3333">Hero bets</font>, MP2 calls, <font color="#CC3333">CO raises</font>, SB calls,

Ugh, what should I do now?