Hello dear
Understand your concern
I think you need psychiatric consultant and immediate treatment:
I think you have
anxiety due to
phobia to particular reasons like exam.
Advice for you:
Be relax first and be positive.
Just Go through exam with good preparation and do not think about result.
Treatment:
Psychotherapy
Relaxation therapy
Do not spend time alone
Read in library or with friends and do discussion of study
Cognitive behavioral therapy
Life style change: Healthy diet, adequate sleep, good company, excercise
Avoid alcohol, caffeine and smoking
Drugs:
Benzodiazepam: alprazolam
SSRIs: citalopram
Olanzapine and pregabalin
But it should be taken after consult to psychiatric.
And do not stop drug without consult the doctor.
Hope this may help you
Best regards
Dr. Sagar