Im on the button with 6

5

at a table full of limping fish one of which will call down his whole stack with bottom pair and buy back in so I'm switching gears and playing a lot of cheap hands in position. So i call 2 limps...sb folds bb calls.
Pot: $9 flop is 3

4

7
It checks to me and I KNOW im getting at least a call if i bet so $7 it is.
I get 3 calls so now pot is $37.
Turn: K
Check around to me.
OK, heres where I'm not sure if i played the hand right. I know I have the nuts as well as a baby flush draw but how scared of higher flush coming in should I be? I pretty much decide to fire about 60% of the pot here & I'm pretty sure that at least 1 of the guys is calling. But after my $20 bet they all fold.
Maybe i should've slow played it there? I can't help but think I left a little value on the table. Thoughts?