How do I recover from extended absence

I am a A2 student studying Geography, Psychology and Philosophy at sixth form, and I am really struggling to recover my grades after I was unable to work for over 3 weeks due to serious illness.

Originally I requested that the school sent me work home to complete while I was unable to come in and my teachers sent me lesson powerpoints and resources to complete. However after a few days the pain progressed to a level were I was unable to move or sleep, let alone work.

Now I have over 3 weeks worth of work piled up and I'm currently sitting mock exams on content that I have not learnt let alone prepared for and revised. I am also incredibly behind on my EPQ project which I need to find time to complete by the 19th March, as well as 4 resit exams I also need to work into my revision.

I was on top of things before I became ill but now I feel like I'm drowning in work that I can never escape from. Every second I spend catching up the missed lessons, I get further behind in my current classwork which sets me back behind again. I can't sleep properly and have had literally no social life in an attempt to try and get all this work done but it's just not working and is beginning to really get to me.

How do I sort myself out of this situation? Exams and other deadlines are rapidly approaching and don't want this to screw up 2 years worth of hard work!