AQ flop top two pair, met with large raise on flop

[CmnDwnWrkn]

Should I assume a set here? Or is he raising this much with AK, a flush draw, or something else enough for a push or call here to be profitable?

Full Tilt No-Limit Hold'em, $0.50 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

CO ($50)
Button ($33.05)
Hero ($53.65)
BB ($48.70)
UTG ($45.30)
MP ($10)

Preflop: Hero is SB with A[img]/images/graemlins/diamond.gif[/img], Q[img]/images/graemlins/diamond.gif[/img].
UTG calls $0.50, MP checks, <font color="#666666">2 folds</font>, <font color="#CC3333">Hero raises to $3.75</font>, BB calls $3, UTG folds, MP folds.

Flop: ($8.25) Q[img]/images/graemlins/heart.gif[/img], 2[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $5.5</font>, <font color="#CC3333">BB raises to $24.5</font>, Hero???