Flopped straight....critique my play/laydown

Party Poker No-Limit Hold'em, $ Hero (8 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

saw flop|saw showdown

MP1 ($24.75)
MP2 ($14.21)
CO ($28.90)
Button ($28.90)
SB ($5.30)
Hero ($29.67)
UTG ($5.35)
UTG+1 ($5)

Preflop: Hero is BB with 4http://www.flopturnriver.com/phpBB2/...miles/club.gif, 2http://www.flopturnriver.com/phpBB2/...es/diamond.gif. SB posts a blind of $0.10.
UTG calls $0.25, 2 folds, MP2 calls $0.25, CO calls $0.25, Button calls $0.25, 1 fold, Hero checks.

Flop: ($1.35) 5http://www.flopturnriver.com/phpBB2/...iles/spade.gif, 3http://www.flopturnriver.com/phpBB2/...iles/spade.gif, 6http://www.flopturnriver.com/phpBB2/...iles/spade.gif (5 players)
Hero bets $1.5, UTG folds, MP2 folds, CO calls $1.50, Button calls $1.50.

Turn: ($5.85) Khttp://www.flopturnriver.com/phpBB2/...iles/spade.gif (3 players)
Hero checks, CO bets $4, Button calls $4, Hero folds.

River: ($13.85) Qhttp://www.flopturnriver.com/phpBB2/...iles/heart.gif (2 players)
CO checks, Button bets $5, CO folds.

Final Pot: $18.85

Results in white below:
Button doesn't show.
Outcome: Button wins $18.85.

Someone has a spade, and its not you. Sucks to laydown flopped str8s, but good laydown here.