25NL - TPTK on turn, but I get donked on a flush board

[CazicT]

Villain: 40/10/1.17 40 hands

OK, pretty standard up until the turn, I hit my TPTK and he donks me for a small bet... Since he called the flop bet I figured he probably had something, though he is kinda loosey goosey donk so he could have just overs.

The bet is so small I couldn't resist, is this OK to make this call?

On the river, i'm getting 5.5:1 to call, I have to call right?

PokerStars No-Limit Hold'em, $0.25 BB (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

MP1 ($5)
MP2 ($15)
MP3 ($35.25)
CO ($22.20)
Button ($23.75)
SB ($18.50)
BB ($18.25)
Hero ($27.70)
UTG+1 ($23.80)

Preflop: Hero is UTG with K[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/club.gif[/img]. MP2 posts a blind of $0.25.
<font color="#CC3333">Hero raises to $1.25</font>, <font color="#666666">7 folds</font>, BB calls $1.

Flop: ($2.85) 4[img]/images/graemlins/heart.gif[/img], 8[img]/images/graemlins/spade.gif[/img], 8[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
BB checks, <font color="#CC3333">Hero bets $2</font>, BB calls $2.

Turn: ($6.85) K[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets $2</font>, Hero calls $2.

River: ($10.85) 7[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">BB bets $2</font>, Hero ...