Tough Laydown?

[xwillience]

villian is 16/9/1.7

Party Poker 2/4 Hold'em (8 handed) FTR converter on zerodivide.cx

Preflop: Hero is CO with K, K.
2 folds, MP1 raises, 1 fold, Hero 3-bets, 3 folds, MP1 caps, Hero calls.

AA KK QQ JJ or AK

Flop: (9.50 SB) 8, 5, 3 (2 players)
MP1 bets, Hero raises, MP1 3-bets, Hero calls.

here is where im almost positive im beat.... its the way he bet so fast that has me almost positive that im beat

Turn: (7.75 BB) 4 (2 players)
MP1 bets, Hero calls.

nothing really has changed so im sticking with it.... only one hand beats me so i dont feel like i can lay this down yet

River: (9.75 BB) 8 (2 players)
MP1 bets, Hero calls.

still no overcards....

Final Pot: 11.75 BB

opinions? am i scared or do you feel that betting speed can be a tell? Do you play this the same way?