Want to concentrate on my studies.

I presume you exams start from 05 Mar and not 05 Jan.  It seems that you took it easy from beginning of the academic year and now panicking as you are closer to your exams which is anxiety that is making you feel uncomfortable. Plan your study pattern, by just revising all the subjects and attempt as many model question papers as possible that will get from CBSE website.  This will keep you motivated towards preparation and keeps you awake. Having said that, sleep without any exam anxiety or fear for good 7 to 8 hours, when you wake up don't sit on your bed /cot or even in your room as the place of your study matters a lot. Don't go for any medication, drink plenty of water, consume seasonal fruits,  avoid junk food, eat only 60% of your stomach capacity.  Go for brisk walk atleast 30 minutes. All these keeps your body and mind fresh and active. If required go for a quick health check up to rule out any deficiencies such as Haemoglobin,  B12 or Vitamin D.