Like everyone said on here, it happens to everyone. I once shot a buck (the largest I've ever had a chance to shoot in my LIFE) and dropped him. Since he dropped about 125 yds away from me and I could see him in plain sight, I watched him through binox for 15-20 minutes with absolutely NO movement. I got out of the stand and headed his way and when I got 50 yds from him, he JUMPED up, stared at me for about 2 seconds and sprinted off. I was in shock. My rifle was slinged over my shoulder so I couldn't do anything- and in utter SHOCK. I went right where he was laying, NO BLOOD. That was extremely frustrating. The only thing I can think of is that I hit him REALLY high and he though he was hit worse than he really was. Probably grazed his backbone. Once he heard me coming, he jumped up got the adrenaline and took off.
...and on that day when my strength is failing, the end draws near and my times has come, still my soul will sing Your praise unending, ten thousand years and then forevermore!