Level 6 (100/200) of a $20 buy in tournament on pokerstars. There are about 140 out of 550 left.

I have about ~T2800 chips left, the average is about T4600 at this point.

The table has been playing very tight/timidly for the most part. I have won a lot of pots without showdown and many many small preflop raises have gone around with everyone folding. I think that my table image is pretty tight although I have been caught in a couple of what might have seemed like bluff attempts (like folding to reraises). Up until several hands before I was one of the chip leaders. I raised and then called an all-in reraise with AKs that went down to runner-runner flush from A3s. This left me
one of the short stacks at the table.

For the hand in qustion I am in CO and my hole cards come QQ. Folds around to a MP limper. I raise to 600 and the limper calls (everyone else folds).

Flop comes: 9 [img]/images/graemlins/spade.gif[/img] K [img]/images/graemlins/club.gif[/img] 6 [img]/images/graemlins/spade.gif[/img]

villian (not sure if that is proper terminology) checks. I bet 600 into the T1500 pot. Villian calls. (Villian started the hand with T7000 btw)

Turn comes: 6 [img]/images/graemlins/club.gif[/img] Villian bets T1000. I have about T1600 left at this point so if I'm calling, I'm going all-in.

I thougt about it for a while and I eventually folded (without showing) because I didn't think he would bet without something. I couldn't see him calling with something like A9 or lower, it just didn't fit my thoughts about him. That left (in my mind) only hands that could beat me (trips, quads, overpair, etc.) In retrospect, an A-high flush draw (or something similar) could have been a possiblity but it wasn't something I seriously considered at the time.

In any case, after I folded, Villian shows me: A [img]/images/graemlins/heart.gif[/img] Q [img]/images/graemlins/spade.gif[/img] [img]/images/graemlins/frown.gif[/img]

...So I want to be a better player and I know that what is most important is whether I made a good decision, not the fact that I probably would have won had I not made that decision.

I'm concerned because one of the thoughts that was going through my mind was I didn't want to go out in a large (for me) buy in tournament when my opponent could so easily have a hand that beat me. I had worked so hard to try and not make rash decisions up until that point and I didn't want to just lose it all in one dumb click. I know that this fearful psychology could be clouding my judgment but I don't think that it necessarily means I made a bad decision. Hence, why I am really unsure.

Thoughts? Would you have played the hand differently? How and why?