Is it normal this happened its very creepy

Yesterday I was watching tv with my mom I was sitting on the floor and my mom on the sofa she had been taking pictures of the cat so she had her phone and she accidently takes a picture while holding her phone angled towards the table and the floor in the background.
She's shook when she sees the result of the accidental picture because in the background you can see my lower half.... standing up.... The picture is of the floor and of my legs, I am standing up turned towards the sofa not the tv, you can also see a little bit of my sweater. Yet when she took the photo I was SITTING DOWN right there next to the sofa on the floor... SITTING turned towards the tv.... Time stamp on the photo lines up.
Someone please explain to me why in the photo I am standing up infront of the tv turned towards the sofa when in reality I was sitting down???? That cannot have been me so whos in the photo and why wearing the same clothes as me??????? Can someone explain????? Is this bad????