A levels and unconditional offer

I feel like I'm going to get B/C in English literature, B/C in Psychology, B in EPQ dissertation (worth half an a level) and an E or U in Biology.

I have an unconditional offer and I've sorted everything out. But honestly, I'm more stressed than before because I know I don't have to do well but I have my pride and I feel overwhelmed and I don't know how to get amazing grades. I've never struggled like this before and I honestly don't know who to talk to about it.

I know it sounds like rubbish but sometimes I stress in my room about it and I feel sick or hopeless. I'm excited for uni and I really like it, but my a levels are making me feel unusual. I intend on trying hard. But it's weird; I feel like even more is expected of me because everything is set in stone. Does this make sense?
(sorry, I've been feeling unlike myself for a while and I don't know how to explain this feeling)

Thanks

Kim x