Oh, my god, Thalia, what a heartbreaking story! I can certainly understand why you can't erase that image from your mind. So, so sad.

I used to live in the country and drove 15 miles to arrive at my workplace. I often went to work before daylight and came home in the dark. My vet became accustomed to me calling her at odd hours, as I gathered an injured rabbit, cat, dog, bird, or even, a gopher tortoise into the blankets and towels I kept in my car. If her clinic wasn't open, she would leave the comfort her home to meet me there. Most of the injured animals did not survive but they at last they didn't suffer any longer and passed in a warmer/cooler place with tender hands soothing them.

I, too, have strong memories of those animals that keep me awake at night.