Here's how to check if Facebook shared your data with Cambridge Analytica
https://www.theguardian.com/technology/2018/apr/10/facebook-notify-users-data-harvested-cambridge-analytica
People who fear their information may have been used by Cambridge Analytica can go to a new help page
Facebook has started the process of notifying the approximately 87 million users whose data was harvested by the election consultancy Cambridge Analytica.