Review Your Mistakes: Identify where you are going wrong and assess what mistakes you are making. Revise the topics again if you feel like because if the concepts are not crystal clear then you might make those mistakes again.
Taking Too Much Pressure: You are allowed to rectify your mistakes and enhance your performance here so there is no need to take any toll on your mind. These are practice sessions to preapre you for the main exam. Dont worry!
Time Management: If you are stuck at a question then move forward to the next, dont kill off all your time on a particular section plus divide your time according to the weightage of the questions so that you can complete your exam in the given time.
Ask for Help You can always ask for guidance and help from your mentor or guide. There should be no shame in asking the same doubt ten times. You can literally ask for any kind of help from them.