You just need to sort of accept you can't get that time back, but you can use your remaining holidays effectively. I would recommend that you make notes for each of your subjects (don't really need to do this for English or maths), doing all the topics or as many dot points as you can do (since some dot points you may not understand and require further help from a teacher or tutor to understand). For maths choose a textbook or if you already have one, find out what topics your school is doing next and then work your way through the textbook exercises maybe 2-3 sets a day (depending on their length). This should provide you a solid foundation before going to school, but if you do have time try to do some past paper questions from sites like thsc online. In terms of English you should probably read or watch your texts and try to just compile sort of a basic table with quote, technique, effect, link to rubric (might a bit hard this last bit). This table you can improve later and then convert into a generic type of essay when you are required in school that you can memorise or if you don't memorise essays you can just memorise the table. Overall you can spend the whole day doing this if you have the will power but if not then you should at least do 3-4 hours a day.
