Welcome to HCM,
After going through your history Hypertension and Osteoarthritis, as you have checked blood sugar it is normal, but diabetes must be ruled out then other causes should be considerd.
We should know are you overweight as 43 years is young age for OA, are you taking any drugs for pain and any antidepresants,which may cause dry ness of mouth and some times mouth breathing
may cause dryness,there are many disease which can cause this.A Repeat GTT Glucose tolerance Test
may reveal true status.
Even polydipsia that is intake of water too much can cause this problem.
or kidney problem.
It is desirable to check with physician and investigate accordingly to know the cause then if required you may consult a Endocrinologist
Good luck to you