NL50:WTF??? 66 completes str8 and gets C/R all in (don´t get it)

[bussolini]

Villain is solid and about 20/12.
I can´t believe what he does there ?!? Am i calling that with my (2nd nuts).
I don´t get his line at all... Can he hold the nutz with just calling my c-bet on the flop ? No hit, and gutshot?? Or did he plan to float? Then, when i check Turn, is he really gonna check that to me ? When every hand like AA,KK or set of QQ is afraif of that Str8 draw that hits?
I feel so bad about that hand, cause i really experienced that those kinda bets are the nuts like 97% of the time...???

Help !

Poker Stars - No Limit Hold'em Cash Game - $0.25/$0.50 Blinds - 5 Players - (LegoPoker Hand History Converter)

SB: $66.75
BB: $41.80
UTG: $30.00
Hero (CO): $63.75
BTN: $67.80

Preflop: Hero is dealt 6[img]/images/graemlins/heart.gif[/img] 6[img]/images/graemlins/club.gif[/img] (5 Players)
UTG folds, <font color="red">Hero raises to $2.00</font>, BTN folds, SB calls $1.75, BB folds

Flop: ($4.50) 5[img]/images/graemlins/spade.gif[/img] 8[img]/images/graemlins/heart.gif[/img] 7[img]/images/graemlins/diamond.gif[/img] (2 Players)
SB checks, <font color="red">Hero bets $3.00</font>, SB calls $3.00

Turn: ($10.50) Q[img]/images/graemlins/heart.gif[/img] (2 Players)
SB checks, Hero checks

River: ($10.50) 9[img]/images/graemlins/spade.gif[/img] (2 Players)
SB checks, <font color="red">Hero bets $8.00</font>, <font color="red">SB raises all-in to $61.75</font>, Hero is freaking out ...

cause it would be a spot to bluff like every hand away with my line? geeeeee, WTF ?