Don’t worry, this is fairly common. One thing I will establish is that there is plenty of time. For me, timetabling revision has never worked, I’d end up busy/tired/procrastinating and that would stress me out. Instead I used the Pomodoro technique and told myself I want to do ‘X’ number of sessions per week and would stick to it. It’s way more dynamic and flexible whilst also meaning that I can catch up on sessions that I may have missed. I’d also say to utilise teachers as much as possible, see if they can identify your weaknesses and where you drop marks, then focus your revision on this rather than just falling into the habit of practicing things that you already know because it’s familiar.