Anxiety while studying: what to do?

Hi! I (22, F) have immense anxiety around studying.

Don't get me wrong, I love absorbing knowledge, but every time I put myself behind my desk, I get REALLY painful stomach aches. Doesn't matter what time it is in the day or what subject I want to study, it's instant. My body (fingers etc) feel very cold to the touch, but I'll be sweating like a horse and I can't sit still for even 1 second without feeling panicked.

I used to be an A+ student in high school before COVID, but since then I have this anxiety around studying. Maybe I'm afraid I'm not doing enough? That I won't pass the exam? I'm currently undergoing interviews to find out wether I have ASS/AD(H)D. So I hope someone, maybe, can relate to me?

Anyone else with this experience? Does anyone know how I can fix this?