I see this quite often with people. I don't know if Bangalore has sleep clinics but I think you should go to one. My theory (not worth a dime

) from what you're telling me; with the waking up during the night and being tired even after a normal amount of sleep, indicates you're not getting the quality of sleep you should be getting. One possibility for you waking up could be because you stop breathing (unbeknownst to you).
Find out if you can get a Polysomnography done. It just requires you to spend one night at a clinic/hospital to see if any of these issues exist. Then you can get it treated and I can almost guarantee you'll see a difference.