you should try on these college. I think you can get admission in one of these colleges.

NIT Srinagar, NIT Agartala, NIT Arunachal Pradesh, NIT Manipur, NIT Meghalaya, NIT Mizoram,NIT Nagalanad, NIT Puducherry, NIT Sikkim, NIT Uttrakhand, NIT Andhra Pradesh

may be You don't like these places . But if you want to go nit in this year only then you should to go. If you are not okay with these options. Then you should improve your self through taking one year gap. and make a proper time table and then follow that.