Combo vs nutter

[cbloom]

No Limit Hold'em Ring Game (6 max) , 6 players
Blinds : $1/$2

Stacks:
UTG : $200
MP : $246 (Hero)
CO : $200
BTN : $95.50
SB : $209.20
BB : $157.60

Pre-flop: (6 players) Hero is MP with 7[img]/images/graemlins/spade.gif[/img] 8[img]/images/graemlins/spade.gif[/img]
UTG folds, <font color="#cc0000">Hero raises to $7</font>, 3 folds, BB calls.

Flop: 6[img]/images/graemlins/club.gif[/img] 7[img]/images/graemlins/club.gif[/img] 5[img]/images/graemlins/diamond.gif[/img] ($15, 2 players)
BB checks, <font color="#cc0000">Hero bets $11</font>, BB calls.

Turn: 3[img]/images/graemlins/spade.gif[/img] ($37, 2 players)
<font color="#cc0000">BB bets $20</font>, Hero ...


Villain is very aggro, bluffy, loose, likes to "outplay" and bully people with big bets. This turn donk is probably a feeler, maybe with a monster, maybe with air, he's trying to see if I will raise or just call.

So, raise or call? (why?) Do I need to hit my draw? What to do on the river if I don't hit?