// Also mysteriously my history shows nothing except for today on pc or ipad //
I am now wondering if you are talking about email files and not system files. If your documents were in emails, then someone one could either guessed your password, or someone other than you may have it. Logging into your email account can be done from anywhere if they have your password. It is then easy to delete all your emails in your inbox and sent box, and the therefore will not be visible on the PC and iPad, when you next open email on either device.