you make the call!

[Dominic]

2-5 NL, $500 max buy-in

In a previous hand, Hero traps Villainess on turn with an overpair on a ragged board - knowing Villainess had a lesser overpair. Villainess raised all-in with 77, Hero called with QQ...river was a 7. Hero loses $300 and doubles-up Villainess.

An hour later, Hero has roughly $450...Villainess has him covered.

Hero is in SB with KsJd. One limper, Hero tries to buy pot with $25 bet...BB (Villainess) calls, limper folds.

flop: KdQd6d

Hero checks.
Villainess bets $75 into a a $55 pot.

Hero goes into the tank. What hand would Villainess do this with?

Certainly not the nut flush....and it's not a total bluff, not with such a large bet, right?

So my choices are:

The Ace of Diamnods?
Maybe a smaller flush?
She hit a piece of the flop and is making sure any draw Hero has is expensive?

Hero decides he's more than likely ahead of 2 of those options, and has the 2nd nut flush draw, to boot...AND since the Villainess has shown an inclination to get all her chips in the middle with the worst of it - the Hero pushes.

Villainess calls, shows Td9d. No diamond on the river and Hero is busted.

Was my push completely asinine? Did I let the previous suck-out cloud my good judgement? Or was my thought process reasonable?

Thoughts and a kick in the nuts would be appreciated.