Ornella,
The exam changes at the end of this week. Starting 26-March-2018 PMI only offers the updated PMP exam, which is based on the PMBOK Guide Sixth Edition. And unfortunately, if you have not yet booked your exam then it is highly unlikely that you are going to find a single available spot anywhere in the world. Everyone has been rushing to take the exam before the change and there are likely no seats available any longer.
Please read this article, since you are going to have to regroup and prepare to take the updated exam:
www.project-management-prepcast.com/free...ok-guide-6th-edition