I made a bad fold and am beating myself up about it

[BigBiceps]

There were horrible players out in force yesterday due to the holiday and I won 8 buyins in 4000 hands at the NL100 level.
Then last evening things were back to normal with alot of the regulars, but still some bad players.

I played this hand, I have QQ in the CO, and raise to 3.50, and the SB calls (he is a 11/0/2.5) over 1000 hands and a solid regular. Flop comes QT8 all spades. He bets, I raise, he 3 bets small, I call. Turn rag. He bets 2/3 pot, I call. River rag. He bets $25 and I fold. He turns over KK with the king of spades. It was $25 to win $100 and I folded top set because I thought he had the flush.

Obviously, it is not the money because I won 8 times that much, but I can't stop being angry with myself.

How do I move on and not be so angry at myself for this mistake?