Am I playing K's like they are A's?

yo guys, it's been a while. a little update: i've recently been playing NL100 6 max on empire and pretty much been owning the game (roughly 8 BB/100). so i guess all is well, but i'm always trying to get better. so recently, i went through my PT stats to look for possible leaks in my game. i may have found one: i seem to be playin k's too hard preflop. this happened to me twice the other day. the first hand, i am button and dealt kk. MP (average stack) raises, i reraise, he pushes, i call. he sets his pocket Q's on the river. oh well, i made the right move. a few hands later, i am once again dealt kk in late position. MP raises, i reraise, he pushes, i call, he shows AA and i feel like a donk.

here's my question to all of you guys who are probably better than me. how often do you fold KK preflop to an average stack, heads up? do you ever fold that? i always seem to stay in the hand in this situation, and i thought this was a +EV play in the long run. obviously, there may be exceptions, like if i see a re reraise all in from a huge rock (say 5%/3%). i never really see a huge rock like that at this level though. so do you ever fold KK preflop, and if so, under what circumstance do you fold it? i'm sure i'll get plenty of different answers, so let me know on that. thanks.

--solids