Help Me Pass My Exams

I am currently undertaking my GCSE exams, but have started falling behind. I'm not sure why this is, as I have always tried my best in school. I am convinced it is to do with stress, however. I do not perform well under stress, and I can say for sure that I am stressed with all this business about picking colleges, apprenticeships, etc, never mind the stress of my upcoming exams. In order to help me with these exams, I would hope to purchase revision textbooks, but the full set I need to help me best will be very expensive.

I have tried to get a job, but all the places I've looked won't hire me until I'm 16 (I'm 15 currently). I have always tried my best, but I feel I can perform better than I am currently with the right tools. I put together a list of what I needed, and it worked out around £250! I don't have the money for this, but I understandingly would like to pass my exams, so I thought I'd come here...

I put together a list of what I need, for proof of the amount. I have bought some of them with what little money I have, but need help for the rest.
I would appreciate it very much if you could help.

List - http://amzn.eu/dzLzyXo