Ray, 

no need to worry just be the hardest worker in the room. JEE MAINS is tough but not the toughest exam. In order to score good marks you just need to be consistent and hard working. 

Study your concepts thoroughly,  forget whatever had happened in Jee Main 2019. Let that not spoiled your mood nor demoralize you. 

Do mock and sample paper as much as possible. It will help you increase your speed and you will gain confidence in your ability and it will help you explore problem which you may have not encountered while studying the chapter. 

Srudy regularly be honest in your efforts and have a faith on yourself. You will definitely be able to score good marks next time. 

Have a regular revision schedule, always remember revision is important. No need to study for 14-16 hrs a day just study for 4-6 hrs a day with full focus and in July 2020 you will find yourself studying in any IIT/NIT . And you will cherish when you peers will call you IITian/NITian.