Checkraised on a terrible flop

[Ghazban]

UB .25/.50 blinds, villain and I both have about $50. I have him covered by a buck or two.

I'm UTG+3 w/ A[img]/images/graemlins/heart.gif[/img] A[img]/images/graemlins/club.gif[/img]

Villain openraises to $1.75 UTG+1, I reraise to $6. All fold to him and he calls.

Flop K [img]/images/graemlins/diamond.gif[/img] 9 [img]/images/graemlins/diamond.gif[/img] 3 [img]/images/graemlins/diamond.gif[/img] (~$12.75 less rake)

He checks, I bet $12.75, he pushes for ~$42 total. I know I'll see AdKx and QdQx much of the time, KK/99/33 sometimes, and AdQd rarely (players at these stakes will often slowplay the flopped nut flush). Given that I can't be ahead by all that much and I might be way behind, do I have to fold this?