50NL Good use of blocking bet?

[Milky]

No reads on villain IIRC. I didn't want to get blown off what may be the best hand on the river, but at the same time this just felt wrong... comments?

Poker Stars, $0.25/$0.50 NL Hold'em Cash Game, 4 Players
LeggoPoker Hand History Converter

UTG: $56.60
BTN: $11.10
Hero (SB): $47
BB: $15.05

Pre-Flop: 7[img]/images/graemlins/heart.gif[/img] 8[img]/images/graemlins/heart.gif[/img] dealt to Hero (SB)
UTG calls $0.50, BTN folds, Hero calls $0.25, BB checks

Flop: ($1.50) 6[img]/images/graemlins/diamond.gif[/img] 9[img]/images/graemlins/club.gif[/img] 8[img]/images/graemlins/spade.gif[/img] (3 Players)
<font color="red">Hero bets $1.50</font>, BB folds, UTG calls $1.50

Turn: ($4.50) 3[img]/images/graemlins/spade.gif[/img] (2 Players)
<font color="red">Hero bets $3.50</font>, UTG calls $3.50

River: ($11.50) A[img]/images/graemlins/club.gif[/img] (2 Players)
<font color="red">Hero bets $3</font>