studying

I’m from the uk and I’m sitting my AS (first year) level exams in three weeks. I am ridiculously stressed right now. I can’t remember anything I revise, nothing will go in. I got all U’s (no grade) in my mock exams and I don’t know any more now than I did then. I think I’ve tried everything. If I don’t get a certain grade I’ll be kicked out of my college and I live in a rural area so there’s nowhere else for me to go and I don’t want to watch all of my friends and my boyfriend go away off to university without me whilst I’m stuck with no grades because I just can’t remember anything. I don’t even know what to do anymore I don’t know if there’s anything my teachers can do to help me at all can someone here help me maybe? i don’t know what to do anymore please help I’m so desperate