Dropping further maths

I did 2 out of 3 of my A2 maths exams alongside my AS ones last year. I intended to do further maths but got a bit depressed and let myself get behind. I did all the notes for AS but feel like I’m too late to get myself to where I need to be with it in time for exams. Should I withdraw myself from the AS further maths exams and focus on my 2 a levels and 1 core 4 exam remaining. I have offers from all my universities this year, but I’m not sure if natural sciences is the course for me. If I withdraw my application from them, and reapply for dentistry (2019 entry), is it likely that they will have an issue with the fact I did A2 exams early (and so have a lower workload for year 13)?

It always says what their policy is in the entrance criteria. I havent seen anyone punished fr taking exams early. Presumably you will still have 3 A levels to apply with once you drop FM?