Hello dear, exams are meant to assess our strengths and weaknesses so that we can use this knowledge in future, they are not meant to be the end of the world. Be calm and study. Make a daily schedule, keeping your overall course in mind, study in short capsules of 30 min with 5 min breaks in between. Take out time for recreation as well, maybe an hour of cricket, half an hour of music, half an hour of reading short stories etc. Go for regular 20 min walk in morning, meditate- simple pranayaam for 15 min morning and evening. If you still feel anxious consult a counselor, he may refer you to a psychiatrist if there is a need for medication.