Heat olive oil in a large stock pot. Sauté onions until softened, then add garlic and cook until fragrant. Add sausage, breaking apart with a wooden spoon until well browned. Add tomatoes and cook for 1–2 minutes to thicken. Add carrots, basil, and oregano. Taste, season with salt and pepper, then simmer on low heat for 30 minutes. Add zucchini and tortellini, then cook for another 10 minutes or until the pasta is cooked. Remove from heat and let sit for 20 minutes before serving.