( increase water intake is not only cause of diabetes
mellitues),as u checked ur blood sugar and its normal...kindly mention what the name of test for sugar u did. It would be good that u should have ur Fasting blood sugar of abt 8-10 hour and plus random blood sugar.
kindly mention ur age always, the symptoms u described required specific further workup as below
please do check ur blood cp,
serum k and serum Na
and Urine D/R in order to detect serum osmolarity.
it will be Golden pearl i ur diagnosis and treatment to have T3/T4/TSH
surely u will be diagnose and get rid of complain..
Feel free to ask after having ur reports