NL10 - With nut flush, board pairs on river, get re-raised. Help!

[jamez_kerry]

PokerStars No-Limit Hold'em, $0.10 BB (8 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

MP1 ($9.85)
MP2 ($8.95)
CO ($4)
Hero ($9.70)
SB ($9.95)
BB ($1.65)
UTG ($7.55)
UTG+1 ($11.25)

Preflop: Hero is Button with 4[img]/images/graemlins/heart.gif[/img], K[img]/images/graemlins/heart.gif[/img].
UTG calls $0.10, <font color="#666666">1 fold</font>, MP1 calls $0.10, <font color="#666666">2 folds</font>, Hero calls $0.10, SB completes, BB checks.

Flop: ($0.50) A[img]/images/graemlins/heart.gif[/img], 3[img]/images/graemlins/heart.gif[/img], Q[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(5 players)</font>
SB checks, BB checks, UTG checks, <font color="#CC3333">MP1 bets $0.5</font>, Hero calls $0.50, SB folds, BB folds, UTG folds.

Turn: ($1.50) T[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
MP1 checks, Hero checks.

River: ($1.50) Q[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">MP1 bets $1.5</font>, <font color="#CC3333">Hero raises to $3</font>, <font color="#CC3333">MP1 raises to $7.9</font>, <font color="#CC3333">Hero raises to $9.1</font>, MP1 calls $1.20.

Final Pot: $19.70