Re-sitting A2 modules due to mitigating circumstances.

I attended a relatively bad school - it's rated inadequate by ofsted and has a 31% 5 A*- C pass rate at GCSE. I achieved the best GCSE results in my school's history - 8A*, 2A,B and was predicted to get A*AAA at A-level. However, due to various mitigating circumstances that were out of my control - didn't have a Biology teacher for 4.5 months and so had to self-teach 2/3 of the course, had severe chronic undiagnosed anemia ( when it was diagnosed the doctor was surprised I was even alive, let alone in full-time education) and my granddad was diagnosed with advanced caner of the stomach - I performed very badly and only achieved AACC. I decided to take a gap year and resit some A2 modules in order to improve my grades. However, I will not be resiting the entire year, only the exams
I've been predicted grades A*AAB and was hoping to apply for medical sciences/ biomedicine at top 20 universities. Do you think repeating the A2 modules will put me at a disadvantage despite the mitigating circumstances? Should I mention them in my personal statement, the reference or call up each university and explain the situation?