Villain screams "I made my flush!"

[NDHand]

Party Poker No-Limit Hold'em, $ BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Button ($37)
Hero ($103.05)
BB ($99)
UTG ($66.94)
MP ($166.55)
CO ($80.80)

Preflop: Hero is SB with 8[img]/images/graemlins/diamond.gif[/img], 8[img]/images/graemlins/heart.gif[/img]. Hero posts a blind of $0.50.
<font color="#666666">2 folds</font>, CO calls $1, Button calls $1, Hero (poster) completes, BB checks.

Flop: ($4) 8[img]/images/graemlins/spade.gif[/img], 3[img]/images/graemlins/club.gif[/img], 5[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(4 players)</font>
<font color="#CC3333">Hero bets $3</font>, BB folds, CO calls $3, Button folds.

Turn: ($10) T[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $7</font>, CO calls $7.

River: ($24) 2[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $11</font>, <font color="#CC3333">CO raises to $34</font>, Hero folds.

Final Pot: $69

PAHUD hadnt kicked in yet and this guy didnt do anything out of the ordinary. His play on all streets screamed of flush draw and his actions on the river confirmed it. Since the 2 couldnt have possibly made 2 pairs or a set, it's either the flush or a bluff (perhaps the unlikely straight). Given the way villain played the hand, I dont think im good often enough here. Anyone calls here?