What key topics for history gcse exam- a divided union? URGENT PLEASE HELP?

Then I'd do 1945-1970 just to be safe. And calm down, everything's gonna be ok. Just study and prepare yourself, get plenty of rest, and eat adequate meals. Try not to stress out to much. With the way these exams are today, you would only have to get about half of them correct to pass anyway. Just review your material and make sure you grasp it. Also, take breaks every once in a while and do something you enjoy doing for a few minutes. That way you'll feel much less stressed out and ready to get back to work again.