This is usually a result of sugar withdrawal. The first week on your new eating plan can be difficult depending on how much sugar and refined carbohydrates you were previously consuming. The good news, it usually last only a week or so. There is light at the end of the tunnel. Tips to help; eat small meals more frequently, increase your antioxidant intake, and increase your glutamine intake. You can also try natural anti-inflammatory nutrients (turmeric, cayenne, bromelain, white willow bark, licorice root, devil’s claw, ginger, boswellia).