is it possible to go from failing to AAB-AAA in five months before a levels?

i chilled throughout year 12 because i was burntout by yeaer 11. But it leaked into y13 and in my last mocks i got BDU. Ive applied to russel groups and im anxious as i havent heard back and my grades are lower than the requriements (im hoping my personal statement will be good) realistically im not getting in so clearing is my only chance of getting into my top uni birmgingham. Even though ive been flopping mocks ( in y12 I got CDE and Cs in one subject Ds in another and E/Ds in the third ) with no revision. Im planning on making flashcards on all the content for my sujects and ill start memorising them then in march i will bang through past papers up until the real thing in may. From now until then i have five months. Is it possible to go from super low grades to As? Im aiming for AAB but triple As if i feel im able to do so at some point. Has anyone ever turned it around from really bad grades in y13 to As in the real thing?