You don't need to be get tensed. If you want to crack this exam you need to be self motivated and determined. You can first focus on the chapters which have more weight-age in the exam. You can also go through past year problems to know about the paper pattern and level of questions. Try to solve mock test papers to know your strength and weakness and to know where you stand among other competitors. You can also use below tool to know about the important topics for your preparation. You can check your preparation level and where you stand with recommendations and improvement plan. Click on the below link- www.engineering.careers360.com/prepmeter/jee-main?icn=jeemain-cp&ici=forum