routine river/overplayed river?

[detruncate]

Party Poker 1/2 Hold'em (6 max, 4 handed) converter

I know... 6-max is HUSH... but I thought the river play might be interesting to at least some of you.

Played a lot of (at times) terrifically bad 1/2 6 last week in an effort to close the gap to my challenge competitor (~17,300 hands in 6 days -- not mind-blowing by any means, but it's a new record for me by quite a bit). 4-tabling in a semi-stupor by this point, but reads are:

UTG has been loose/passive for the most part, but seems capable of folding a small piece in the face of aggression.

SB is loose/passive pf, but likes to take shots -- he'll bet any piece when checked to, but generally doesn't mix it up. I haven't been at the table very long, but SB has already taken down a couple pots on the turn/river by betting when checked to, and it seems to be a big part of his game -- he's had at least a pair every time he's subsequently shown down.

Preflop: Hero is BB with A[img]/images/graemlins/spade.gif[/img], 5[img]/images/graemlins/club.gif[/img].
UTG calls, <font color="#666666">1 fold</font>, SB completes, Hero checks.

Flop: (3 SB) J[img]/images/graemlins/spade.gif[/img], T[img]/images/graemlins/diamond.gif[/img], 2[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, Hero checks, UTG checks.

SB may or may not bet a pair here. He probably leads with a J. He might bet a T. I don't think he bets a 2. UTG could have anything.

Turn: (1.50 BB) 6[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(3 players)</font>
SB checks, Hero checks, UTG checks.

SB will almost certainly bet the turn with any pair (except maybe 2s) after the flop checks through. UTG often still won't bet a middling or bottom pairs -- his aggression numbers are miniscule.

I'm playing pretty weak/tight by this point -- not only am I just looking to hit my hand total for the day, I'm still coming out of a 220+ BB slide that didn't do anything good for my game or my psyche. Long story short, I'm pretty sure a turn bet didn't occur to me. Should it have?

River: (1.50 BB) 5[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
<font color="#CC3333">SB bets</font>, <font color="#CC3333">Hero raises</font>...

Ok... here's where it gets interesting(?). Remember that the decision was made in the context of what I know about my opponents. However, I'm not sure I properly took pot size into account. I'll leave further explanation of my thought process for later so as not to taint things.

Did I make the right decision, or is this overplaying at its finest?

Thanks in advance.