3/6 flopped FD & gut shot in raised pot

[SgtJake]

Villain is 25/10/3 over a moderate # of hands. He likely sees me as nitty. I'm on the button. We're heads up on the flop.

What do we do preflop? What do we do after he cbets considering we've flopped a gutshot & and FD?

POKERSTARS GAME #11190660371: HOLD'EM NO LIMIT ($3/$6) - 2007/07/28 - 23:17:37 (ET)
Table 'Polites V' 9-max Seat #2 is the button
Seat 1: eyegetpaid ($666.25 in chips)
Seat 2: HERO ($582 in chips)
Seat 3: LuV222PoKHeR ($431.35 in chips)
Seat 4: Bagarn72 ($507 in chips)
Seat 5: stinsojo ($882.65 in chips)
Seat 6: 67mark ($457.60 in chips)
Seat 8: Filthy999 ($1290.90 in chips)
Seat 9: VILLAIN ($624.60 in chips)
LuV222PoKHeR: posts small blind $3
Bagarn72: posts big blind $6
*** HOLE CARDS ***
Dealt to HERO [Kd Qd]
stinsojo: folds
67mark: folds
Filthy999: folds
VILLAIN: raises $15 to $21
eyegetpaid: folds
HERO: calls $21
LuV222PoKHeR: folds
Bagarn72: folds
*** FLOP *** [8d Jd Ah]
VILLAIN: bets $36
HERO : ????