22s: TPTK spot makes me vomit

I don't have the history on this one, but I remember most details.

Blinds: 50/100.

Action: EP limps, LP limps, I have red AQ on the button. I'm chipleader with around 3000. No real reads, except for lots of loose calls preflop. I limp. SB limps and BB checks. 5 to the flop.

FLOP (500) Q[img]/images/graemlins/club.gif[/img] 7[img]/images/graemlins/club.gif[/img] 3[img]/images/graemlins/heart.gif[/img]

Checks to me on the button. I bet 400, happy to take it down, and giving 2.25 to 1 on flush draws. SB calls as does LP limper?!

TURN (1700) 5 [img]/images/graemlins/diamond.gif[/img]

SB leads for 500. He has about 1500 behind. LP folds. HERO?? What hands check/call that flop and weak lead the turn? Is it a huge mistake to limp here preflop when I'm not sure I can get heads up with a 300 chip raise?