Daughter told me she's not my biological child

Throwaway account. Me (M/43) Dad of a teenage girl (18) and two sons (12, 8). Small town, everyone knows everyone kind of thing. I was at the bank today and one of the bank tellers was a friend of my older brother's upset and I asked her what was wrong and she said her boyfriend had broken up with her, made me feel bad.<br>She offered to talk about it with me and we went for a walk after work. She's a lot younger than me, but she's been in school since she was a teenager.<br>Anyway, I asked if she was okay and we talked for a while. She told me my brother must have a big heart to be such a good listener, like she was surprised. I said I wasn't my brother, but she said I must have been. I asked her to explain and she said she had thought I was him because of something my "daughter" had said. I don't know what she means, and so I ask. She told me my daughter had said I was her uncle. I don't have any sisters, I'm the youngest so I was confused.<br>I asked her again what she meant and she said I must have known. My daughter and her family went on a camping trip with us a long time ago and my daughter said I was her uncle. I don't know, maybe my daughter was joking. I asked her if she was joking, but her eyes were brimming with tears so I knew she was telling the truth.<br>I didn't say anything and I went home. I have been in shock since it happened. I don't know how to feel or what to feel, everything is just strange.<br>I went upstairs after I got home and saw a picture of me and my daughter. She's the most precious thing in the world to me and always has been. I started crying and I don't know why. I don't know what to do, or how to feel. I don't know what's going on.<br>I just know that I need to get to the bottom of this and find out if this is true.<br>So I guess this is my to do list for the day.<br><br>1. Talk to my wife and see if she knows anything.<br>2. Talk to my daughter and see if she knows anything about this.<br>3. If both of them deny it, see a doctor.<br><br>If it's true, I don't know how I'll feel. I feel like I've been hit by a truck, like the rug's been pulled from under me. I feel like I've been punched in the gut and don't know how to react. I don't know what to do if it's true. I don't know what to do if it's not true. I'm not sure how I feel about it yet. I know my family is everything to me and I would never stop loving my daughter no matter what.