Hi Abanindra,
Congratulations on your victory.80% is a good score.
Don't bother about what your parents or neighbor say.
Look you need to understand that each one of us are different.Everyone possess a unique set of talent.You just need to find out what your real passion is and then follow your guts.Board exams scores though they are important, they don't decide your destiny.Only you can shape your destiny remember that, and not a score written on a piece of paper.
Never compare yourself with others.We all have different capabilities.You may be good at something other's aren't and vice versa.So just chill.You have done well, now put all your energy into thinking and deciding what you would like to pursue further because that's the need of the hour.
Remember what Einstein said "Everybody is a genius. But if you judge fish by its ability to climb a tree ,then it will live it's whole life thinking it's foolish"
Talk with you parents calmy .Incase your suicidal or depressive thoughts are persistent then do  seek a doctor's help.
I can assure you that you will do very well in your life.
Have faith in yourself.
Hope this helps