QUESTIONI can't help but feeling before even my first exam I have left things too late and am on my way to well and truly mucking up my GCSEs. The thought of this is distracting me from revision. Have I left it too late? I would be grateful for your advice.
ANSWERFirst of all, and most importantly, try not to get stressed out over your revision!

A small amount of quality revision is really helpful and you don't need to spend endless hours reading notes.
If you feel you would benefit from it, design a simple revision planner for the upcoming weeks. You can either set aside a day for each subject or do parts of multiple subjects each day, whichever you feel comfortable with. Concentrate on the parts you find hard, as well as the topics you can't remember very well because you did them so long ago.
Doing lots of practice questions where appropriate is always helpful because you can get a lot of revision done in a small amount of time using this method, and it is particularly effective when you have your notes alongside you to answer the questions.
For some subjects, you can make up some small, concise revision cards for you to carry around with you. Writing out and re-reading the main points of topics will help you consolidate the knowledge you already have.
Hope this was helpful. All the best!