So today I had my last A-level exam, OCR A chemistry paper 3. I thought that after my last a level, I was going to be so happy and relieved, yet today is genuinely one of the worst days of my life and I can't stop crying and breaking down every time I think about how horrible and how badly my exam went today.My firm is pharmacy at Manchester university and the entry requirements are ABB with an A in chemistry. I think I will get around a B in both biology and history (no way I'm getting an A in either though), and I thought I would manage to get an A in chemistry until today. My paper 1 exam went really well and using the unofficial mark scheme I think I got around 73-74 which would be right around the boundary for an A. My paper 2 exam went even better and I think I got around 77-80, also around the boundary for an A for that paper. I was extremely confident and only did one past paper the day before my paper 3 exam (which I didn't even manage to finish in 1hr30) and so I was very ill prepared and I know its all my fault and I can't believe I was this stupid.So today, I get to the exam and I immediately see the 6 markers be on the only topics I did not revise for in a while (I completely forgot how to make a standard solution and probably got maximum two marks for that question). I completely messed up ALL of the mathsy questions due to panic (I got 93 for the amount of water when it was meant to be 2??), I ran out of so much time and missed out probably 10 marks worth of questions, I answered most questions completely wrong because I was panicking so much in the exam and trying not to cry even though looking back I could have definitely answered it correctly, and when I came out the exam everyone was saying it went well and the answers that everyone got I didn't get at all. I would be lucky getting even 30 marks in that paper and I'm tearing up even thinking about it. There is absolutely no way I'm getting an A and getting into Manchester which is my dream university.I feel like such a disappointment to my parents and to myself. I got amazing GCSE's getting pretty much all 9s and have decent predicted grades of A*AA yet I would be lucky to get BBB and will probably realistically get BBC due to shear laziness and panicking during exams and I won't even get into my insurance.I genuinely cannot stop overthinking about how this exam went and crying to the point where my voice is gone. I genuinely don't know what to do to stop stressing about the exam. I'm dreading results day where everyone will find out I'm a failure. Being smart was the only thing going for me and now I'm not even that. I don't know what to do.