There's no magic formula and there really isn't any intelligent "flushing out" you can do. You feel bad because you've eating a lot of processed food, carbohydrates, calories, food volume, and sugar. You will feel better when those leave your system and you start fueling your body appropriately. Here are some suggestions -- just know these aren't instantaneous.:
1. Take a nap. Your body is probably dealing with a blood sugar roller coaster. If you are tired, listen to your body and give it some extra ZZZs.
2. Drink more water. Drink coffee and tea in moderation. Stop drinking milk, juice, soft drinks, alcohol, sports drinks, etc.
3. Eat a lot of high fiber, low calorie veggies like celery, cabbage, and broccoli. These foods are great nutritionally, but they will also help your body naturally eliminate what is in your GI tract.
4. Get in some serious sweating by doing some high intensity aerobic activity whether that is taking a spin class or going for a run or whatever.
5. Avoid all sweeteners except stevia and monk fruit.