I think my opponent thinks I'm FOS

[Harv72b]

My first hand at this table, and I post in the BB. About 20 datamined hands tell me nothing about the opponent except that he's not extremely anything.

Party Poker 5/10 Hold'em (8 handed) FTR converter on zerodivide.cx

Preflop: Hero is BB with K[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/club.gif[/img].
<font color="#666666">4 folds</font>, CO calls, <font color="#666666">2 folds</font>, <font color="#CC3333">Hero raises</font>, CO calls.

Flop: (4.40 SB) Q[img]/images/graemlins/diamond.gif[/img], 6[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, <font color="#CC3333">CO raises</font>, Hero calls.

Turn: (4.20 BB) 4[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">CO bets</font>, <font color="#CC3333">Hero raises</font>, <font color="#CC3333">CO 3-bets</font>, Hero calls.

River: (10.20 BB) 6[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">CO bets</font>, <font color="#CC3333">Hero raises</font>, CO calls.

Final Pot: 14.20 BB
<font color="#009B00">Main Pot: 14.20 BB, between CO and Hero.</font>

Thoughts? I was calling a 3-bet on the river.