My maths teacher and tutor both have given me a lot of textbooks but I foudn excel is the best for me. And i also think going through past papers leading up to exams is always the best way to make sure you know your stuff and to revise anythign your not sure on.
But, if you find the course easy and still cant remember anything in exams then its ur actual exam technique that needs help. The best way to remember things is to link topics and formulas to each other so you keep your mind organised and thoughts organised, and to try visualise the questions as you answer them. Also silly rhymes (I use Silly Old Harry Can Actaully Hang Ten On Australia= SOHCAHTOA) to exagerrate points and this will help you recall facts in the exam.
I also use a highlighter and highlight all key words in all of the second section. This usually triggers somethign in your memory and I find it helps me a lot.
Other than that, just take deep breaths and no stressing or you will have mind blanks. Hope that helps a bit.