Set the stock pot over medium heat and add the olive oil, allowing it to get warm. Add the onion, carrots, and celery. Cook and stir for about 10 to 15 minutes, allowing the vegetables to sweat, not brown. Add the garlic, salt, and pepper and cook, stirring for another 5 minutes.
Add the turkey meat and cook, stirring for 5 minutes. Pour in the chicken broth and the leftover gravy. Add the rosemary and thyme and bring to a boil.
Add the egg noodles and bring back to a boil. Cook over medium heat for about 15 to 20 minutes, then turn the heat down to low and cook for another 20 to 30 minutes.
Remove the rosemary and thyme sprigs. Stir in the lemon juice and serve.