The only time I ever hit a walk off HR was my first game of my senior year in HS.
I felt like I didn't have control over my body. By the time I realized what had happened, I was almost in LF because I had took such a wide turn rounding second wooooing as I went around the bases with both arms raised in the air like an idiot.
I distinctly remember giving our head coach (who was third base coach) a high five and yelling "It's my year nag!". I proceeded to go 7 for 41 that year.