WSOP Circuit lay down of KK's. Not sure it was correct.

This was the first event, $300 buy-in at the Caesar's Indiana Circuit event last week.

I was card dead for the first 3 levels and had only played one hand until this hand came up. In that hand I limped in the CO w/ JTo after several limpers and folded to a bet on the flop.

I was down to T1300 chips halfway thru level 3 w/ blinds at 50/100 when this hand came up. I look down at two red kings in EP2 and raise it up to T150. My thinking at this point was how unforutnate it was that I wouldn't get a single caller b/c of my tight image at the table.

Much to my surprise, I get reraised to T400 by MP2 who had about T2200. He had been in maybe 18% of the hands so far. My read on him was that he was a semi-tight passive player who hadn't done anything out of line. I had also watched him when he was in other hands as to his breathing and general demeanor.

Everyone folds back around to me. I have to say that normally, I would shove all my chips in here at this point but I decided to call as I couldn't imagine this guy reraising me with anything other than AA's or AKs. In addition, when he reraised me to 400, he did it forcefully and I hadn't seen him act so aggressively during his other raises. I studied him for a second, thougt his breathing was a little more rapid than other hands I'd seen him in, and decided to just call.

The flop came 7s2s8c. I was down to T900 chips and checked to him. He threw out T400 chips almost immediately. He hadn't acted like this in any of the other hands I'd seen him play to this point.

I went into the tank. After about 3 minutes, I folded face down but not before casually allowing the guy to my left see my hand. I surmised he had AA's and there was no way I was ahead.

Was this a bad fold? Should I never fold KK's in this spot?
BTW he showed the table his hand.

Thanks for your comments.