You were ahead. Here's my reasoning:

Everyone knows that you can't bluff anyone out of a $120 pot with a $2 bet. Therefore, your bet on the river must be a bet-for-value with anywhere from a monster hand (e.g., 3rd pair, top kicker) to a merely strong hand (such as 2nd nut no-pair). Your bet gave away your hand, and your opponents made the correct read. The surprising thing isn't that they read you, it's that all three of them had the courage to trust their read and fold. That's a masterful laydown in my humble opinion and one that I personally would not have had the courage to make.

HardToBeat, Norrlander, and Kangar, I salute you.

PP