the very first thing you should do after every failure is to analyse, discover and accept the reason of your failure then comes the part of comeback
after that you have realised or more apt to say analysed your weak points more commonly known as loopholes in your jee preparation, the very first question you should ask from yourself is that “will i be able to screw my mistakes and surpass my limitations if i give myself 1 more chance for jee??”
if the answer comes yes, then without any second thoughts about “what if this, what if that, what will my cat think of me, what will my dog say, will the cows accept my offerings bla bla bla” you should begin planning your strategy for the next chance you have blessed yourself with.
see all of us are well aware that no failure is permanent, but most of us loose against our pessimist self when it comes to turn our failures into comebacks of success, so one more important thing is keep your calm and turn both deaf ears + blind eyes and a no smell sense nose, towards people who discourage you or try to tell your limitations, because how can someone know something that didn’t even exists ryt!
so get back to the furious you, stand again and stand firmly and make a promise to yourself that this tym. you are surely gonna make it to your dream college and you wont back down even a femtometer before you achieve your goal.