few of the questions you need to answer like-how many times do you get up in night to pass urine.
Do you have to strain while urinating, stream of urine.?
You should do some basic tests to find out if kidney
problem exists like urine routine, RFT. Blood sugar, ultrasonography
You may be required to do some special tests like Urine/ serum osmolarity
The test results may give some clue... consult your doctor..