My dog just died, what should I do to get over it?

Today I went to a neighbor's house for dinner with my mom and came home alone and found my dog had been hit by a car. I was devistated. His name was Jack. My mom found him on an old country road as a puppy. He was frail, sick and in need of care. We took care of him and he became the most playful character you could want in a dog. He always licked you no matter what, he was loving, and was always willing to cuddle. He liked outdoors, he especially liked trying to bother our other dogs. He skipped and frolicked in the grass so happily you could tell he loved being alive. We've had him for roughly 2 years, and today, I found him, covered in blood, with a broken leg. He had been hit by a car. Unfortunately, Jacks playful and silly nature lead him to chasing cars. He was one of my best friends and I am having a lot of trouble getting over it. He was only 2 years old. I keep calling him in my head so that he could come back but he won't. I don't know what to do.