Fold on flop ? turn ?

[pirlouit]

B2B 1/2 (6 handed)

Preflop: Hero is UTG with J[img]/images/graemlins/club.gif[/img], Q[img]/images/graemlins/heart.gif[/img].
<font color="#CC3333">Hero raises</font>, MP folds, CO folds, BU calls, SB calls, BB calls.

Flop: 8[img]/images/graemlins/diamond.gif[/img], 9[img]/images/graemlins/club.gif[/img], J[img]/images/graemlins/heart.gif[/img] (4 players)
SB checks, BB checks, <font color="#CC3333">Hero bets</font>, MP calls, <font color="#CC3333">SB raises</font>, <font color="#CC3333">BB 3-bets</font>, Hero calls, MP folds, SB calls

Turn: 2[img]/images/graemlins/spade.gif[/img] (3 players)
<font color="#CC3333">SB bets</font>, BB calls, Hero calls.

River: 6[img]/images/graemlins/club.gif[/img] (3 players)
<font color="#CC3333">SB bets</font>, BB calls, Hero calls.

Final Pot: many BB

Where is the fold ?
On the flop ? or the turn ?
I decided to cold-call 2 bets with top pair + gutshot; was it a mistake ?

On the turn, I was planning to fold if BB raised, but he never did, then I chose to calldown (hesitated to fold the river though)

Thx for your advice