Preflop: Hero is MP with Q, K.
1 fold, Hero raises, 1 fold, Button calls, SB calls, 1 fold.

Cool

Flop: (7 SB) Q, T, J (3 players)
SB bets, Hero calls, Button calls.

Should have definitely raised here (IMO)

Turn: (5 BB) K (3 players)
SB bets, Hero calls, Button folds

Good players would probably raise here, I'm a wussy, so the K scared me and I would probably just call too.

River: (7 BB) 3 (2 players)
SB bets, Hero calls.

Gotta call here.

I think you missed the raise opportunity after the flop. But what do I know??