My Double Or Evil Ghost?

Let me get straight to the story. I am 21 years old and stay with my parents. I have a two year old son but at the time when this occurred he was only a few months old.

Being a new mom you are, most of the time, very drained and all you want is sleep. Well, one night my mom offered to take the baby for the night so I could get my full night's rest. Being as sleep deprived as I was, I didn't hesitate one bit. Well, my son being only about 2 months old, woke up regularly for his feeds during the night. As my mom woke up at about 6am for his final feed, I had gotten up for college.

Now her bedroom is at the end of the house down a long passage. Also, the bathroom is right outside her bedroom door, so naturally when she heard my slippers coming down the hallway she called out to me to take the baby, dress him, feed him and bring him back to her before I left for college. She called out but I did not respond, so she leaned over in her bed that way she could see right down the passage and there she saw what she thought was me standing looking at her, pressed up against the wall looking at her. She said, "What are you doing?" before realizing the girl standing there was not me but looked exactly like me just with a different blank kind of look on its face. She turned over in her bed in fear and held my baby before noticing it was gone.

Later I got up, went to the bathroom as usual, feeling great after a full night's sleep and that was when she had told me what had happened.

When I first bought my baby home I always felt like someone, particularly an old man, was watching, standing over his crib and was sometimes to afraid to go into the room were he slept so I moved him in with me. Things have been a little better now. I don't feel a presence anymore since we had the house blessed.

What could this have been? Any help would be appreciated.