My first year bowhunting I did the same thing, knocked the deer right off it's feet, could see my arrow sticking out of it. All I could think was "oh no, it's going to run across the main road and people are gonna be pissed about the stupid hunter and his porcupine deer" , it circled around not knowing what had happened and I go to knock another arrow, it looked up and noticed the cause of it's issue... and took off. NYbuckboy and I searched for a while but never recovered that deer