[25nl] Big leak of mine, bigpairs becoming 2nd pair

[latvaniemi]

This exemplifies something i think is one of my biggest leaks, atleast it feels like it. Pairs like jj-qq when i either bet or 3bet them flop and an overcard comes out. I usually handle cbet them 2/3 of the pot regardless of position. Is it that wrong? Should i cut down on it... feels like i'm giving the money for free by doing this.

Ps. How would you handle the river?

$0.1/$0.25 No Limit Holdem
5 players
Converted at weaktight.com

Stacks:
UTG (<font color="#0000cc">$5.16</font>)
CO (<font color="#0000cc">$12.54</font>)
BTN (<font color="#0000cc">$8.23</font>)
Hero (<font color="#0000cc">$20.40</font>)
BB (<font color="#0000cc">$39.07</font>)
[UTG posted $0.25]

Pre-flop: ($0.6, 5 players) Hero is SB Q[img]/images/graemlins/diamond.gif[/img] Q[img]/images/graemlins/spade.gif[/img]
UTG checks, CO calls $0.25, <font color="#777777">1 fold</font>, <font color="#cc0000">Hero raises to $1.25</font>, <font color="#777777">1 fold</font>, <font color="#777777">UTG folds</font>, CO calls $1

Flop: K[img]/images/graemlins/spade.gif[/img] 4[img]/images/graemlins/club.gif[/img] 6[img]/images/graemlins/spade.gif[/img] ($3, 2 players)
<font color="#cc0000">Hero bets $1.75</font>, CO calls $1.75

Turn: 8[img]/images/graemlins/spade.gif[/img] ($6.5, 2 players)
Hero checks, CO checks

River: 2[img]/images/graemlins/heart.gif[/img] ($6.5, 2 players)
<font color="#cc0000">Hero bets $3.75</font>, CO calls $3.75