I need some study advice?

I am very behind in my study. I am finding myself having to reteach myself things from earlier in the term in order to continue learning. I have 2.5 classes I need to study for and 8 full days to do it in. Is it too late? I started study at 8.a.m today and worked through until 5p.m. If I do this for the whole 8 days, do you think this will be suffice? The classes are all maths based. I have done a worksheet for the class each week so am I overstressing or am I in trouble?