Okay, your school/college/sixth form should help you apply for special consideration, in which case you'll still get grades but they'll come from mock grades, grades from your AS year if you're in A2, or coursework grades. Talk to your education provider about this and they should be able to help you out and explain what's happening. I couldn't sit one of my exams due to illness, and I missed a lot of coursework for that subject as well. They took my overall grade from my work from the previous year and the coursework that I had completed.