My entire life there have been many occassions where people confront me thinking I am their friend, daughter[you would think a mother would know their own daughter], neice, cousin, etc.. I just have that common face I suppose. It happens all the time to a lot of people and I don't think that's anything unusual.
Although I do believe in Doppelgangers..I have seen my stepmom's "double walker".

It was sometime during the summer while I was visiting my father. My siblings and I always sleep in the livingroom so sometimes we are awakend by my stepmom or father when they're making their way through the livingroom to the door, so they can leave for work. Well this particular morning I woke to see my stepmom leaving for work, but I instantly fell back to sleep as soon as the door shut behind her. An hour or so later, I was awakened again but this time by her walking back into the apartment. I watched her make her way through the living room, down the hall, and into the bedroom while she talked silently on her phone. I just assumed she was let out early from work. I couldn't go back to sleep so I got up and started my morning routine early as my siblings slept. I went to the restroom and I could hear my stepmom talking on the phone from down the hall, and I could see the lamp light from the bottom of the door. Even when I entered the restroon I could hear her through the wall. I didn't think much of it so I went on as normal. After a while she got silent in the room so I looked toward the door and noticed the light was off, so I figure she's just asleep since its still early.
Later my siblings wake up and start making a lot of noise so I quieted them down and told them if they keep up the noise, they were going to wake up their mom. I was surprised when I heard them say "Momma's at work!"
I told them "No she's not, she came back home." For a minute or so I tried to tell them she was home but they just looked at me like I was bogus.
So I let it go and decided to wait for her to come out of the room, but she never did.
It wan't until she walked through the door later I freaked out. I asked her if she had came back to the apartment early in the morning but she said she never did.
I SWEAR on my own life that she walked through that door and into the bedroom.
Later I learned about doppelgangers and came to a realization that what I saw was Her doppelganger simply mimicking her.

Also, I thought I should post my experience.
When I was a kid I moved away from away from the town my grandmother lived in, we moved around an hour and a half away from her, a few years later I was in the supermarket with my mum (my grandmother's daughter) and I saw a woman who was identical to my grandmother, same coat, same hair and the exact same glasses, she even had eyes like my grandmothers who has one that is slightly squinted due to an operation she had when she was a child. We yelled for her attention and she didn't even acknowledge us and walked around the corner, we followed but the woman was gone. When we got home we rang my uncle who lives with her and he informed us that she was in Berlin visiting her family and her flight wasn't due in at the airport for another 2 hours.

I've also been told of incidents where people have seen a girl who they believed were me, but blonde. I've never been blonde in my life but this girl is apparently identical in every way other than hair colour, she even supposedly has the same dress sense.

My 17 year old son showed me a facebook page of this girl at his school and no # the girl was a dead ringer for me. i was totaly blown away.

I worked ten years at an organization that employed over 100 people. I became best friends with a few of them and ended up meeting my husband there as well. Long story short, my best friends, co-workers whom I worked with for 10 years and boyfriend (now husband) would constantly say they saw me in places I never went to before. They said this person (they ended up naming her "Sabrina") even drove the same vehicle I did. Very weird!

about 11 years ago, I am driving to my sisters, One street away, going slow, all of a sudden I see "Me" walking down the road. same hair, glasses even. I slowed and went past him looking stunned. Why didn't I stop and ask who he was? damned if I know . It just had me blanked out for a while.Seeing my self? so close to my sisters place? When my daughter was younger, a few years before this she saw me on the bus and in the street a few times, maybe three, even talked to me but he didn't reply. As Shatner says , "Weird or what?"