You mean to start September 2018 or 2019? The deadline was ages ago for 2018.
You can apply to medical schools [ in the correct year] that dont place as much emphasis on GCSE.
Your main target is your A level grades due to the policy against resits. Get the grades.
Be warned lots of foundation year medicine will not be open for you. Some of it is for people with the wrong subject A levels or contextual offers. You will need to check. its not an alternative for people with lower grades. Check entrance criteria.