Frustration

I have my math exam next Wednesday and I'm really getting frustrated. I always aim for good grades, but in math, it's too hard for me. I'm not usually the type of person to just give up, to act like I don't care. Reading the first few pages and really concentrating and putting my efforts on it, writing down numbers and really focusing on understanding, and the result, a mess of numbers on my paper which don't make any sense. And the worst part, I actually have no clue what I've been writing down, though I had tried my best trying to understand it. Or, if I start understanding a bit of what I'm doing, in few seconds I just get lost.