I'm on button w/ KK, 3 limpers before me, I raise to 5x BB. One caller.

Flop comes AAQ .. no flush draw. I bet 8x BB, other player raises all-in, then shows me QTo when I lay down.

How would you have played this one? Bigger preflop raise with that many limpers around? Can I do anything but fold with that kind of call preflop? I'm figuring I'm up against at LEAST an ace.