I think I am way too passive in hands where I'm OOP and I don't really know where I stand. Should I lead river here? What about turn?

As played I was planning to call any river bet.

PokerRoom No-Limit Hold'em, $1 BB (8 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

saw flop|saw showdown

SB ($207.70)
Hero ($95.00)
UTG ($38.90)
UTG+1 ($133.00)
MP1 ($107.20)
MP2 ($105.00)
CO ($75.00)
Button ($48.40)

Preflop: Hero is BB with 5, 2.
UTG calls $1, 1 fold, MP1 calls $1, MP2 calls $1, CO checks, 1 fold, SB completes, Hero checks.

Flop: ($8) 5, 6, 5 (6 players)
SB checks, Hero checks, UTG bets $1, MP1 folds, MP2 raises to $5, CO folds, SB folds, Hero calls $5, UTG folds.

Turn: ($19) 3 (2 players)
Hero checks, MP2 bets $8, Hero calls $8.

River: ($35) T (2 players)
Hero checks, MP2 checks.

Final Pot: $35