Preheat oven to 375°F (190°C) and lightly grease a 9x5 inch loaf pan.
In a large mixing bowl, combine ground beef, breadcrumbs, milk, onion, garlic, 1 tablespoon Worcestershire sauce, eggs, thyme, salt, and pepper. Mix by hand until just combined.
Transfer the meat mixture to the prepared loaf pan and smooth the top.
Bake for 55 to 60 minutes, or until the internal temperature reaches 160°F (71°C). Let rest for 10 minutes before slicing.
While the meatloaf rests, melt butter in a large skillet over medium heat. Add mushrooms and sauté until softened and browned, approximately 6-8 minutes.
Sprinkle flour over the mushrooms and stir constantly for 2 minutes to cook the flour.
Slowly whisk in the beef broth and remaining 1 tablespoon of Worcestershire sauce. Simmer until the gravy thickens to your desired consistency.
Slice the meatloaf and serve warm topped with the mushroom gravy.