If you feel that way, return it or exchange it for something else.
I can't say that I understand the way you feel, because it doesn't bother me that many people have fake and real mono speedies. I bought the bag because I like it, not because I want everyone to know that I bought an authentic bag or because I wanted to be unique, because I don't look around to see what everyone else is carrying before I purchase something.
But I can understand that people will go on and tell you that "you know it's real,...etc., in an effort to change your mind about it, but if you don't have that conviction, and you are worried about being unique, those words won't convince you. So return or exchange the bag.