A funny thing happened

I got up from my recliner and entered another room then returned through the living room to the back bedroom.  I heard a beep from the phone.  I thought it was a text but it was a notification that someone had walked through my living room.  I checked it out and it was me, of course, I am the only one here.  I have this security camera next to the TV which is on all the time.  I can access it anywhere that I have internet service.  It acted new to me tonight.