Turn is where it all went wrong, obv. Hero has TPGK and FD. Action from the villain indicates that TPGK is marginal here. Cheap showdown is preferred. The FD on the turn is slightly less than 20% to hit on the river, and the Q high flush might not be enough to win (if it's a cooler). Small hands play small pots. Unless the river is the Ace of clubs (which means Villain did not have NFD on turn and gives Hero 2nd nuts), Hero should play passively.

Basically, this is a bad spot to attempt a bluff. Not many villains at this level are going to fold the range you put this villain on. If Villain is bluffing, give him/her another chance to bluff on the river and call down only if you have a read that puts Villain on a weak range (which in this case, you have indicated that you don't), otherwise, fold. It looks like you put villain on a range that was ahead of you and anything you could reasonably represent. This situation is very tempting to bluff at, since you know you can't win otherwise, but is almost always going to be spew if you go for it.

Remember: It's not about winning every hand, or even every hand you might have won if you didn't fold; it's about finding spots where you have an edge, and pressing that edge.