Having a feeling of constant thirst is a typical sign of diabetes.
If you have not had a blood test taken to check your HbA1C levels, make an appointment with the doctor again and do tell him that you have constant thirst. The HbA1C blood test measures the average glucose levels in your blood over a 9-12 week period and this gives a good indication whether you are diabetic or not.
Another reason for feeling constant thirst is eating too many sugary foods and as mentioned above could be a sign of diabetes.
Also another reason for feeling constantly thirsty is having too much salt in your diet, and drinking alcohol that will dehydrate you.
With regard to your bad breath, as your oral hygiene is fine and there is no tooth decay or throat infection, you may have a lot of mucus due to post nasal drip. That can make you feel thirsty and give you bad breath. Keep off the milk for a few days as milk encourages the formation of mucus.
If your diet consists of very spicy and strongly flavoured foods with onion and garlic, that will give you a bad breath. If you suffer from stomach problems that also can cause bad breath. Eating raw parsley is supposed to help alleviate bad breath.
You could also buy some mints or mint chewing gum to help against bad breath, it is better to get to the bottom of things. Look at the things that you eat and drink to see if you can made some changes.
Best wishes.
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