There's still hope don't worry. Were your predicted grades about 7/6 for your GCSE's before your mocks?
You will just have to really focus from now till when you take your exams. If you don't have many notes I would suggest looking through all your courses and only writing notes for the areas you are struggling with. This will save time and is also effective. Make sure you do lots of past paper questions and full past past papers for every subject, this will help you narrow down areas to focus on. The CGP revision guides are also very helpful for condensed notes but be careful as they don't contain everything you will need. Some of my friends also found some YouTube videos helpful for science (primrose kitten was the favourite).
Good luck and I'm sure you'll be fine, just work hard till they are done.