Preheat an oven to 350 degrees F (175 degrees C). Grease a 8x8 inch baking dish.
Beat the egg in a mixing bowl. Whisk in the onion, pickle juice, salt, and pepper. Stir in the bread until soggy, then mix in the ground beef until evenly combined. Form into a loaf and place into the prepared pan. Stir together the chopped pickles, ketchup, water, sugar, and Worcestershire sauce; pour over the meatloaf.
Bake in the preheated oven until no longer pink in the center, about 1 hour. An instant-read thermometer inserted into the center should read at least 160 degrees F (70 degrees C).