Hi.. Welcome to HEALTHCARE MAGIC.. As per your query dry mouth is commonly seen in patients who are suffering from thrush but if the dryness continues after the resolution of infection then it has to be taken care of as dry mouth can be due to a number of conditions and Type 2 diabetes or adult onset diabetes is one of the common cause of causing dry mouth and also diabetics are more prone to infections and thrush is one among those.. Stress is another factor that can cause thrush.. As you are gaining weight Hypothyroidism can also be a cause, but any cause can be confirmed only after proper investigations.. The whitish coating that you offer frequently is also due to the increased fungal growth.. I would suggest you to consult an Oral Physician and get evaluated and he can advise you to get your blood sugar, thyroid levels and if any other investigations are required after a clinical evaluation so that a correct diagnosis can be done and treated accordingly.. As far as stress is concerned you can control it by doing meditation, deep breathing exercises as well as if required you can be advised to take anti-anxiety medicines like Lorazepam, but should never take without consulting or advise by your physician.. Hope this information helps.. Thanks and regards.. Dr.Honey Nandwani Arora.