Honestly, if you're serious about getting into medicine then you need to complete a levels, if you don't do well then you can always look for a foundation course but they generally require you to posesses full alevels. For me, though I take essay subjects, I found that the content isnt harder in year 13, its just more fast paced and a lot is going on at once, if youre in year 12 atm, focus on understanding the content and being well organised --dont worry about next year, focus on this one