KK 15/30 at Stars

[LarsVegas]

Im in a 9-handed PokerStars 15/30 game, find K [img]/images/graemlins/spade.gif[/img] K [img]/images/graemlins/diamond.gif[/img] in UTG+1. I raise. Two midpos callers. Small Blind calls.

Flop 5 [img]/images/graemlins/heart.gif[/img] 7 [img]/images/graemlins/heart.gif[/img] 8 [img]/images/graemlins/club.gif[/img]. I bet, midpos raise, small blind bets three. After taking a little bit of time, I am not able to put both of them on a worse hand than mine. I fold. But deep inside i feel a bit weak.

Anyone support me - or strongly disagree?