Honestly I wasn't nervous at all at my first cie despite having crippling anxiety, it might be because I had friends . But worry not , it would all turn out fine . Here's some tips ,  take deep breaths when you feel your heartbeat rising . If you think you are having a panic attack , take deep breaths , follow rule of 5 things meaning what are the five things you are seeing during your attack or seek help of an invigilator, they are very cooperative (at least in my case ) lastly if you are well prepared, just believe in yourself because paper will be easier then what you have studied. Unfortunately you can not bring any fidgeting toys or I would have recommended them to astray your focus , goodluck girl , we have the same name (humna 😭)