IMO you should be worried. AS exams start in May. I know alot of people who did no revision and at least C/B grades. All of the people who got less then CCCC in thier mocks that i know got the same grades in the exam. You can only revise now, not lots of time to grow your intelligence in terms of capability.
If you did not try very hard then there is time to improve.
If you work harder then you should be able to get decent grades.
If you revised for your mocks then your doing something very wrong or DDEE is your realistic grades as it only gets harder.
Good luck, start revising early!!