Dear Student,
It is unfair to test the capability of oneself and God by just abstaining from things you love only.
You will have to do more of what is required for you to pass your exams, which simply means, depending on the difficulty level of your exams you have to spend the maximum time studying/doing what is required.
Additionally you have to give reasonable time for daily necessary activities like eating, personal hygiene, and most importantly sleep.
An exhausted mind without proper nutrition will not be able to concentrate on the complex concepts one is trying to master.
Next Steps
Make a timetable of how you want to study and for how many hours/day.
For eg you want to study for 6 hrs /day , Divide the 6 hrs in slots of 60 mins. In that 60 mins keep a study session of 50 mins with a 10 min break. In that 10 mins , do stretching exercises or go for a quick walk. Ensure you are not on Social media Or watching any webseries Or any other visual distraction.
Once you have finished your 6 hours of study, spend an additional 90 mins revising all the concepts you have learnt through the day.
Health Tips
Do the above daily for 6 days a week and Sunday should be your rest day. Consistently doing this will help you overcome the fear of exams. As Lord Krishna says " Karma karo, Phal ki chinta mat karo".