Guessing that you are taking care of your teeth and it is not about not brushing and flossing or having bad teeth or gingivitis. Check into the foods your are eating and or drinking. Some foods like coffee, garlic, fish and eggs would be a few examples. Do you have any sinus problems or up set stomach issues? They can also lead to bad breath. If you can rule these issue out you may want to speak to your doctor to see if there are any other underling issues that are causing your bad breath.