Button, I was shocked inside, and I felt very much with the deer, which is a creature who was absolutely innocent injured by my driving or will die later because of it, even if it was standing solid on its four legs before running away. I've never met any living creature except mosquitoes. It was a very bad feeling.
I know just what you mean. I was accelerating hard in the Ferrari along a nice straight country road when a farm cat tried to outdrag me, and lost. It shot off to the verge of the road but when I got the car turned round and drove back to where I hit it, I found it dead with its thigh bone sticking out through its skin. It didnt have a collar or any ID so there was no one I could tell, but it was upsetting leaving a dead animal by the side of the road.
It hit the mesh grille on one of the front bumper air intakes. Luckily the bumper is GRP so I could repair it myself. The grille - no more than an 8 inch sqare piece of back painted wire mesh was something approaching £200 from memory.
But it is an upsetting experience accidentally killing an animal. And unlike you I have shot numbers of birds and rabbits. Somehow thats different, maybe because you then eat them.