From what you wrote, I wonder if you are suffering from anxiety. Unfortunately, I’m not familiar with what kind of help is available to you in your country. If it is possible for you to see someone to explore whether medication would be helpful, I hope you will do so. That would give you some immediate relief.
But for a longer term solution, you do need to learn some techniques for managing your anxiety. For that, some sessions with a therapist would be helpful. A book I often recommend to people as a self-help resource is Feeling Good: The New Mood Therapy by Dr. David Burns. Take a little time every day to work on some of the exercises in it. Another source of help can be found here at PsychCentral. Click on the “Find Help” tab and look through the list of support groups.
In the meantime, think about this. Sometimes the way to help yourself is to get out of yourself. You seem very worried about being judged by others. If you could instead focus on helping others in the class to do better, you might be able to lose some of your fear.
Writing to us was an important first step in taking care of the problems. I hope you will follow through and look for the help you need to use your considerable intelligence and achievements as effectively as possible.
I wish you well.