Is it possible to retrieve the data of my servor from yesterday ?

Hello.

If you do not have a backup of yesterday's data such as EBS, you cannot restore it.
Restoring the entire EBS data cannot be done without a backup.
https://repost.aws/knowledge-center/ebs-restore-deleted-volume-snapshot

For example, if it is a WordPress post rather than the entire data, it may be managed by revisions, so I think it is possible that the post data can be restored.
https://wordpress.com/support/page-post-revisions/

Unfortunetely, it's a problem with the template and we have to edit the page one by one to fix that.