I'll add that I also like a re-raise on the flop. It makes the hand much easier to play IMO, and you won't have to deal with situations like the one you're in right now, since you can fold the turn if you bet and it's two back to you.
In the current mess, I have a feeling that someone just hit their QJ, or has a better two pair/set, so I would fold begrudgingly. The fact that SB is so aggressive makes this a much tougher decision though.