ok, still on that min-raise pre-flop buzz. Flop I figure opp is drawing, turn I start to feel threatened. Thoughts?

Full Tilt No-Limit Hold'em, $0.25 BB (9 handed) Full-Tilt Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

SB ($23.65)
BB ($31.25)
Hero ($40.20)
UTG+1 ($10.55)
MP1 ($22.50)
MP2 ($15.90)
MP3 ($24.15)
CO ($28.65)
Button ($11.85)

Preflop: Hero is UTG with 7, 8.
Hero raises to $0.5, 5 folds, Button calls $0.50, SB calls $0.40, BB calls $0.25.

Flop: ($2) 9, 3, A (4 players)
SB checks, BB checks, Hero bets $2, Button folds, SB calls $2, BB folds.

Turn: ($6) 9 (2 players)
SB checks, Hero bets $6, SB calls $6.

River: ($18) 4 (2 players)