If it's your personal computer, it absolutely, 100%, CANNOT at all, have any work-related software on it. It has definitely NEVER been inside an office related to your company, NEVER handled by your company's IT department, and NEVER involved in company work. To detach your company from cause, all of these points MUST be 100% true. If you ever brought it to work and put it on the network, if you ever let the IT department install things on it, if you ever left confusion on if it was a company asset in these cases, it likely got loaded with something used inside the company. If you have absolutely NO doubt whatsoever that the company NEVER touched the computer, then it's as distinct from the company as mine. Your company can't randomly pull data from your laptop the same way they can't pull it from mine, or MBP17.David's, or Harleyinlv's.
That said, there was legal barriers preventing random data collection from company computers (or ones with software installed that makes the company thinks they own them). They have to have certain evidence indicating a need to pull data. If they have suspicion of a crime and legal paperwork in place, they may do such a collection. But again, they can't pull data from me, they can't pull data from you, UNLESS you allowed them to install software that enabled it.
I suspect you sent the document to someone who leaked it.