If you made one mistake, it was that you called from the small blind after so many people limped in.
I would not call in that situation with that hand because you have to assume that even if you land top pair on the flop, it's still a difficult call since your kicker is a lowly 7. Someone can have J/10 offsuit and decided to call.
But after the flop, I think yuo made the right call. You were put into an impossible situation. I would have done the same. Betting 3x the big blind is good. You had him dominated but just got unlucky. It happens.
The other night, I raised with Pocket 2s one guy called. On the flop came 2 2 J. The guy calls all-in. I call. He's got Jacks full but I have him beat. On the turn is a crappy 8 that does nothing. On the River comes the last J. Yay me.
