The healing process for Josh McCown began the moment he stepped into the quiet of the visitor’s locker room in the bowels of Hard Rock Stadium moments after the Jets’ devastating 31-28 loss to the Dolphins on Sunday. It was painful. McCown felt physically ill. He had just thrown a telegraphed pass, intended for Jermaine Kearse, right into the arms of Miami cornerback Bobby McCain with 39 seconds remaining in regulation in a 28-28 game. It gave the ball to Miami on the Jets’ 27-yard line and, seconds later, the Dolphins won it with a short field goal to cap a two-touchdown comeback. Suddenly, every positive play McCown made in the game no longer mattered. Not the three touchdown passes he threw. Not his rushing touchdown. None of it. “I was very sick about it,’’ McCown told The Post on Friday in a quiet moment at his locker. “And when you have a free thought, your mind goes straight to that play.’’ But from the ashes of that soul-crushing play came a realization McCown believes will propel him and his teammates forward as they attempt to rebound from a two-game losing streak with a potential season-defining game against the Super Bowl runner-up Falcons on Sunday at MetLife Stadium.