You: "Hm, looks like that flop didn't connect with me, but I showed aggression preflop so I need to do a continuation bet against him. There's two diamonds there, so I want to bet an amount that gives him the wrong odds to go after the flush. By betting this strong he's definitely going to put me on an overpair or something good preflop that held up and get out of the hand, because hopefully he's seen how few hands I've played recently. And let's hit the bet button.... now."

Him: "Hey I have a pair of fives; I call. lol "

He just accidentally outplayed you because you're thinking at the wrong level.