Well done for having a go at this. I flunked all my exams at school because I used to enjoy myself too much at school and never attended half my exams and never did any revision. I decided to do a couple of GCSE's 2 years ago. I did science and maths higher. The science was piss easy and interesting, I got an A and really should of got an A* if I had of put a bit more work in.
The maths on the other hand done my head right in and I really struggled. I have never liked maths and trying to do it 25 years on was a nightmare. Nearly all the students on the night class were mature and within the first term the class had more than halved in size with people dropping out. I put loads of work in revising all the stuff that I hated like algebra, quadratic equations (and graphs), simultaneous equations, vectors, probability, trigonometry. When it came to the non-calculator paper it had loads of basic stuff that I never bothered revising like long multiplication, division, percentages, ratio's etc. It took me a while to get my head around it as I was panicking at first as I knew I had done the revision wrong. The non-calculator paper is by far the worst in the higher exam. I got a B which I was really pleased with as I found it really hard going. I was so pleased to put my scientific calculator in a place that I will never need to use it again once it was over.
I need to do English next, maybe next year. Not a subject I find that interesting but I would guess it is way easier than maths, which is a really dry subject if you are not into it.
Good luck :-)