I also just lost AK heads up to KJ when the flop came KdJd4c and I made a big bet and he called. Putting him on the flush draw, I went all in on the turn and he called. The river was no help and I lost to 2 pair.
I have to say that these sorts of hands are actually more frustrating than a "bad beat" to a bad player. I was right to raise pre-flop. I was right to bet when I flopped top-pair, top-kicker with flush and straight draws. I can't think of one thing I would do differently if faced with AK and that board again.
This hands stands in stark contrast to one I misplayed yesterday. I flopped 2-pair and he turned a higher 2-pair. Bet, re-raise, re-raise, re-raise. Hmmmm, surely he has me beat....call! Honestly, I do know better than that, but I was terribly distracted by things going on around the house at the time. This is one of many reasons I am going to change my online playing habits. I am often distracted at key moments and make decisions I would not make in a live game. Ugghh.