Pressure is easier to carry when you split it into pieces. Big exams are just a lot of small questions.

A large task presented as a single object is heavier than the same work presented as its parts, even though the amount has not changed. An exam is a sequence of individual questions, each of them ordinary on its own. The dread attaches to the whole, which is why the first question nearly always feels better than the hour before it. Splitting is not a trick, just an accurate description.

Break the big thing on your calendar into its real components and write them as a list. Chapters, question types, sections, shifts. Then work one item at a time and keep your attention there.