Did you submit an exceptional circumstances form? If so did you get a doctors letter for it as evidence too?
As for money, migraines don't qualify for any specific student disability payment however in student finance you have two options.
1, you can re sit the year and use your gift year. Every student has a gift year built into student finance so if you fail you can still be paid your money and tuition.
2, you can also submit a compelling personal reasons form. To do this you would need a doctors letter and to speak to your student finance advisor at uni. If granted not only will you get student finance next year but you won't use your gift year in case you need it in future.
Hope that helps you