I found out I’m friends with my sperm donor

So I did <a href="https://glowing.com/glow-fertility-program">IUI</a> and had my beautiful daughter five years ago. When I was choosing a sperm donor I was able to see a picture of my sperm donor as a child. Well I was hanging with some friends and we were showing off our baby pictures to see who was cutest and there it was, the exact photo that was in my sperm donor’s file. I felt like I was in a movie, I almost had a panic attack right then and there, I got so stressed that I actually threw up when I got home. Do I tell him that my daughter is half his dna?? My daughter loves him, he’s like an uncle to her (my daughter often hangs out with me and my friends so she’s pretty close with most of them). I don’t think I can act as if I don’t know he’s my daughter’s biological father.

Little update: So I asked my friend if he had ever donated sperm and he quickly realized why I asked because he’s not exactly stupid. He said that he donated sperm a few times seven years ago when he was low on money. And also, yes it was the same picture, I’m 100% sure because I looked at baby/childhood pictures of donors for hours before actually choosing my donor and he really stuck out of the bunch. My donor’s picture was of a little boy (with ginger hair, brown eyes, pale skin, no eyebrows, and lots of freckles) sitting on someone’s lap showing that he had lost a tooth and smiling. My friend does look a little bit like my donor: he has brown hair, brown eyes, has better eyebrows than me (I’m actually jealous), some freckles and is pale as snow. I just never thought it could be him because what are the odds of that happening right??? Well he said he wants to take a DNA test to make sure so that’s the next move, but I honestly don’t know what he’s thinking about the entire situation (I asked him and he just said he doesn’t know what he’s thinking or feeling atm).