Not sure if this is in the wrong section or not, if it is then i am sorry.

Basically i just wanted to ask a question and to gain some advice. I play NLHE 6-max (Micros :( ) and i have this leak were i feel im always being beaten by the nuts. For example i have KK preflop and i 3bet and i someone 4bets me and i call. The flop comes A27 for example. Now i automatically think they are holding Ax. Or another example im holding AK and flop comes AK10 and i bet and get raised. Now my first instinct is his holding JQ. Is this a mental thing? Or is this because i think its purely Online poker and they are prob holding the nuts. Any ideas how i can overcome this. I feel like i am folding to many hands for this reason. This might sound stupid to some but its worth a try.