Bad flop play?

[MickeyHoldem]

1/3 NL 10-players

MP3 (~$200) read: passive...
Hero (~$600)

Pre-flop: Hero is button with A [img]/images/graemlins/club.gif[/img] 6 [img]/images/graemlins/club.gif[/img]
UTG raises to $10, 2 fold, MP1 calls $10, MP2 calls $10, MP3 calls $10, 1 fold, Hero calls $10, SB folds, BB calls $10

Flop: ($61) A [img]/images/graemlins/diamond.gif[/img] T [img]/images/graemlins/heart.gif[/img] 2 [img]/images/graemlins/club.gif[/img] <font color="blue">(6 players)</font>
BB checks, UTG checks, MP1 checks, MP2 checks, MP3 checks, Hero bets $20, 4 fold, MP3 raises to $40, Hero calls.

Turn: ($141) 5 [img]/images/graemlins/club.gif[/img] <font color="blue">(2 players)</font>
MP3 bets $45, Hero calls $45

River: ($231) 9 [img]/images/graemlins/club.gif[/img] <font color="blue">(2 players)</font>
MP3 checks, Hero bets $100, MP3 calls

Final Pot: ($426)