Preheat oven to 350 F. In a large bowl, combine ground beef, breadcrumbs, milk, egg, diced onion, seasonings and worshtershire sauce. Mix until evenly combined.
Form mixture into a loaf and place it into a greased loaf pan. Bake for 30 minutes.
For the brown sugar glaze, in a small bowl, combine ketchup, brown sugar and mustard together. Evenly spread glaze over the meatloaf and bake for another 20-30 minutes. Let cool for at least 10 minutes in the pan.