hi hemant,

please do not get frustrated. 

with 78 percentile, although you will not get a seat in IITs or NITs.

but you can surely get a seat in good private colleges which give admission on the basis of jee mains score or on the basis of your 12th marks.

also please wait for the last as private colleges offer a seat to the student with lower percentile when there are seats left unfilled.

hope this will help.

all the best for your future!!!