Hi friend, you are probably going through some ‘exam fever ‘. Well you need to only focus in the given syllabus all through out the year not just at the last moment nor by over learning / at the That’s when you feel such a mental blocking that disturbs you .
Next Steps
A few tele counselling (Psychotherapy) sessions will help you to cope up well with this discomfort. Give a chance to the specialist/ Psychologist to suggest the systematic way to resolve your problems .
Health Tips
Maintain a good diet , a bit of relaxation also along with revision work.