Dear, the first thing you should do is not to panick and have faith in yourself. You can do it this time. See whenever you are studying suppose you are solving MCQs overnight or the time you are spending for your preparation. Next morning after waking up try to memorize all the topics you covered , if you can't remember something then consider that particular portion requires some more time. Do it this way so that none of tbe topics leave your brain.

You will present the best version of yourself, stay confident and make a proper timetable to revise a portion you practiced three days back.

More practice, definite success

Good luck!!

See you should learn the concepts very well. When ever you can't solve the problem in repeated times, that means that you have just seen the technique of solving it but the not the concept. So if you wish to get a strong grasp on the concepts you have to revise it every week. See you prepare concepts for  6days a week and keep one hour every day to revise all the things you have studied the previous. This way prepare and revise. On the 7th day just solve problems and do revise all the things you have learn that week. This way you will be able to get the facts revised and it will get stored in your memory permanently as well as you will not forget concepts. Also do a monthly revision of all the things you have learnt before.

To know more about JEE MAINS preparation strategy visit the link below:

https://engineering.careers360.com/articles/jee-main-preparation-tips

I hope this answer helps. All the very best for your future endeavors!