i cant stop thinking

i feel like i'll fail everything and get really low grades. my predicted are pretty high and the exams rn r easy but i can't help thinking ill fail eventhough i revise. I'm on edge cause my college offer for my preferred college is 9/8 and thats just like 15% of the nation and im def not the smartest person or even near that. my mocks were 9-7 but obv mocks just count people in my school and not the whole nation before giving grades.