Otta, my advise to you is,
When you sit the flight planning exam, start at the beginning and finish at the end. You will be suprised at how relaxed you will be during the exam as it is a test on management and stress not really on skill. If you start at the beginning you will slowly work your way through the exam, the key is to not stress about the time. If you do, it will cost. You will find that you will complete the exam, if not then that is ok as your accuracy in the completed questions would have got you over the line.
Good luck.