What did I do wrong here?

Hello,

I'm fairly new to the forums but have been lurking for quite some time. I've learned quite a lot from reading hands posted and suggestions from others. However, I don't understand where I went wrong here or how I could've prevented this. Any suggestions?

Thanks in advance.

PokerStars 0.50/1.00 Hold'em (9 handed) http://216.119.70.224/converter/hhconverter.pl

Preflop: Hero is MP3 with K[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/heart.gif[/img].
<font color="#666666">1 fold</font>, UTG+1 calls, MP1 calls, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises</font>, CO calls, <font color="#CC3333">Button 3-bets</font>, <font color="#666666">2 folds</font>, UTG+1 calls, MP1 calls, <font color="#CC3333">Hero caps</font>, CO calls, Button calls, UTG+1 calls, MP1 calls.

Flop: (21.50 SB) 3[img]/images/graemlins/diamond.gif[/img], 7[img]/images/graemlins/club.gif[/img], 2[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(5 players)</font>
<font color="#CC3333">UTG+1 bets</font>, MP1 calls, <font color="#CC3333">Hero raises</font>, CO folds, Button folds, <font color="#CC3333">UTG+1 3-bets</font>, MP1 folds, Hero calls.

Turn: (14.25 BB) 3[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">UTG+1 bets</font>, <font color="#CC3333">Hero raises</font>, <font color="#CC3333">UTG+1 3-bets</font>, Hero calls.

River: (20.25 BB) T[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">UTG+1 bets</font>, Hero calls.

Final Pot: 22.25 BB