Toast the 5 slices of wheat bread and let cool. I use a food processor to make my own bread crumbs out of the wheat bread when it cools. Then take the onion and sweet bell peppers and put them in the food processor and chop them up pretty fine not quite minced empty out the food processor and put the eggs, oregano and mushrooms in and blend it up and chop it fine. Finally, mix all ingrediants together and let it rest for approximately 1 hour and form a loaf that is packed pretty tight on a sheet pan or pan of your choice. Top with steak seasonning (I use the weber chicago steak seasonning) and bake in a 350 degree oven for approximately 1 3/4 to 2 hours. Top the meatloaf with the ketchup during the last 15 to 20 minutes that it bakes. Pull the meatloaf out of the oven and let it rest for 10 minutes then slice and serve.