Unknown airtag tracking my iphone. What should I do.

So I got this notification. That an unknown airtag has been following me since 5.20am. I do not own any airtag. Neither does my family. And I lock my doors before sleeping. So no chance someone that had put it.I don't know what should I do now. It showed me that someone tracking my location. And showed me the location from my home to work then to home.