Hi, I'm also sitting the exam on Tuesday and I am panicking.. In the two mocks we previously did I got a U both times and I'm predicted an A* - how ironic
Anyway, a common issue is timing: for the first three questions which are 8 marks I'd advise you to spend about 12 minutes on. The 16 mark require about 25 minutes and the final 24 mark should take about 35 minutes.
You should always always read through the sources they give you first and highlight or underline key information (go for the first and last sentences of each paragraph), jot down a plan before you answer the 'Writing' section and keep an eye on the clock, you do not want to run out of time without answering the larger mark questions as this will affect your grade greatly -- just bear in mind every question you miss out is a grade decreased :/
Just don't stress yourself out too much, loads of people are in your position & you're not on your own