Maths Alevel OCR Grade A*

I have AS results as all modules A's and this year i've been doing D1,C3 and C4. I've finished my D1 exam but feel it didn't go to plan and maybe a high B if i'm lucky. Is it still possible due to C3 and C4 being my stronger subjects to still get an A*?

Yes. You need at least 480 UMS overall and at least 180 from C3 and C4 so, theoretically, you could get an A* with 0 in D1.