If you still have any devices that have your old data (cached, etc) it might be worth keeping them powered on but disconnected from the internet, so that they don't end up realizing they should no longer have access and delete what could be the last copy of your data that you can actually access.
Whatever you still have access to (again, from cache, existing browser that's still logged in, etc), start making backups - screenshots, etc.
Whatever you still have access to (again, from cache, existing browser that's still logged in, etc), start making backups - screenshots, etc.