For the Meatloaf:

1. Preheat the oven to 350°F. Line a baking sheet with aluminum foil and set aside.
2. Transfer breadcrumbs to a small bowl and stir in the milk. Set aside for about 5 minutes.
3. In a separate large bowl, combine the beef, pork, onion, garlic, egg, ketchup, Worcestershire sauce, salt, and pepper with your hands.
4. Add the breadcrumb mixture and mix until thoroughly incorporated. 
5. Place the meat mixture on the prepared baking sheet and form into a tight loaf with your hands, about 9 inches long and 5 inches wide.
6. Bake for 50-60 minutes, or until a meat thermometer registers 155°F.
7. Let rest for 15 minutes before cutting into slices and serving with the gravy.

For the Gravy:

1. While the meatloaf is resting, make the gravy by melting the butter in a medium sauce pot over medium heat.
2. Add the diced onions and 1/4 teaspoon salt, and saute until slightly golden, about 3 to 5 minutes.
3. Sprinkle the flour over the onions and stir well to evenly coat. Cook over medium heat, stirring constantly, for about 2 minutes.
4. Add the stock and whisk until thoroughly combined. Cook for another 2 minutes, stirring constantly.
5. Reduce the heat to low and stir in the cream. Cook for another 2 to 5 minutes to slightly thicken the mixture.
6. Season with the remaining salt and black pepper, and serve with the meatloaf.