Flop flush, now what?

[Rupert]

In hindsight I suppose I should have raised the donk lead, but as played do I call or fold? $55 freeze

PokerStars No-Limit Hold'em Tourney, Big Blind is t150 (9 handed) Hand History converter Courtesy of PokerZion.com

CO (t4065)
Button (t9095)
SB (t13785)
Hero (t4710)
UTG (t2565)
UTG+1 (t13553)
MP1 (t5460)
MP2 (t2287)
MP3 (t15135)

Preflop: Hero is BB with 5s, 8s.
1 fold, UTG+1 raises to t300, 3 folds, CO calls t300, Button calls t300, SB calls t225, Hero calls t150.

Flop: (t1500) Qs, 3s, 7s (5 players)
SB bets t450, Hero calls t450, UTG+1 folds, CO raises to t3765, Button calls t3765, SB raises to t13485, Hero ????

Wow. I didn't even see that the SB overpushed and I was already trying to fold. I can put one guy on a set and one guy on a naked As, but I'm having trouble figuring out a situation when you're ever actually ahead here. I think this is a fold.

[footnbaseball]

If you're ever going to fold a flopped flush, this seems like the time to do it.