hero pukes and then calls.
Your turn check is showing some major weakness here. it looks to me like he's picking up on that and trying to steal from you.
I don't see him doing this with the nut flush. He could be doing it with a smaller flush, but if htat's what he's got, then you're still on 10 outs.
But i think he's making a play. maybe something like
7/Q/4/5
hell, he could be playing a set or an overpair really poorly too.
This all being said, i think the range of hands you're ahead of is large enough to warrant a call here. The only thing that scares you is a flush.