Starting stack 15000. Blinds 200/400

Current stack 12000

I open UTG AJ offsuit for 1000

Folds around to cutoff. 3 bets to 2800

Folds back to me I call

Flop comes out AQJ rainbow. I lead out for 3000, he shoves. I figure the only hands he is 3 betting with preflop are AA,KK,QQ,JJ,AK,AQ,1010,99.

I also figure the only hands of those that he shoves post flop are AA,KK,QQ,AQ, and maybe AK. So I conclude I must almost certainly be behind. I fold my AJ showing him, He shows AQ. Someone remarked that I tilted him by folding, but I really didnt think I could beat anything as played. Went on to chop the tournament 5 ways from there.