KK vs. tricky opponent, check-raised on the flop

[Peoples Elbow]

Just got to table a few orbits ago and no stats on villain yet, except that he seems to be very loose and playing well postflop.

1) Did I donk up the flop?
2) Turn check good?
3) I'm assuming everyone's folding this river?

Poker Stars - No Limit Hold'em Cash Game - $0.10/$0.25 Blinds - 6 Players - (LegoPoker Hand History Converter)

SB: $24.75
BB: $40.10
Hero (UTG): $26.10
MP: $42.45
CO: $25.00
BTN: $13.30

Preflop: Hero is dealt K[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/diamond.gif[/img] (6 Players)
<font color="red">Hero raises to $1.00</font>, 4 folds, BB calls $0.75

Flop: ($2.10) 9[img]/images/graemlins/diamond.gif[/img] 3[img]/images/graemlins/heart.gif[/img] T[img]/images/graemlins/heart.gif[/img] (2 Players)
BB checks, <font color="red">Hero bets $1.50</font>, <font color="red">BB raises to $4.00</font>, Hero calls $2.50

Turn: ($10.10) 9[img]/images/graemlins/heart.gif[/img] (2 Players)
BB checks, Hero checks

River: ($10.10) Q[img]/images/graemlins/club.gif[/img] (2 Players)
<font color="red">BB bets all-in for $35.10</font>,
Hero????

Pot Size: $45.20 ($0.50 Rake)