Welcome to the Postman Community! 
No data has been wiped or deleted. You can export your data using the ⚙️ > Settings > Data menu option,from your signed in account. This will allow you to Export all of your data.
You would have also been presented with this during the update where you can choose the option that was right for you and your context.
Just to confirm that you read and agreed to the Postman privacy policy when signing up for your account.
In terms of security and GDPR - You can find all the information regarding this and of all the latest compliance reports here: