Try not to worry about it. I thought it was just going to carry on from A level and so the material would just be like the module C5, C6, C7, C8 etc. However maths at degree is much more pure. It is hard to even explain it to somebody who hasn't started learning the material. What I will say is, do not panic. It might be rather mental at first, but after not long at all it will become a second nature to you and you'll wonder what all the panic was in the first place.
I wish you all the luck when you start your first year and if you ever need help or advice then feel free to message me.