Yes , you can still do it.

All you require is structured planning + Planned Hard Work + Smart Work .

All your work must be smart work.

Smart work means solving quality questions.

Some tips :

1. Gradually increase the level of questions you solve.

2. Solve each and every question in specified time. Don't look into the solutions impatiently. Learn the basics concepts the problem demands.

3. Solve good , quality problems.

4. Pay more attention to topics that are frequently asked in the JEE.

5. Write as many mock tests as many possible. Analyse your mistakes from them and rectify them.

6. Do not neglect your board exams. Study for them seriously. Write mock tests and get evaluated from your teachers

7. Consult your sir and discuss your problems in detail with him.