first thing I would say is calm down and enjoy your break. Bridging work is really not necessary and only does more harm than good. you did amazing in you GCSEs so celebrate and maybe like a week before at most look over the first topic or just an overview of your choices from the exams boards you are going to be doing. sociology in particular for the first few lessons is just GCSE , everything might look hard because you're doing later topics but even if its earlier topics wait till september when you have a teacher ready to help you understand. you seem hardworking and passionate so i promise you will do fineee.