I don't remember the exact moment when it happened, but a horrible trend had begun. Hitting a tennis ball, something that for several years was second nature to me, suddenly became foreign. I began overthinking my forehand, causing it to fall apart. As I hit a forehand, my mind and body disconnected in panic; my swing was unfamiliar, sending the ball to the bottom of the net or over the back fence. In order to hit correctly, I had to...