Dna results...

I was so set on who the father of my daughter was. I was positive the dates and everything added up... dna test came back today and he’s not hers. I don’t know how to feel... I’m scared, hurt, and feel like I’ve failed as a mother.. I’m confused because he looks JUST LIKE HER. Their newborn pictures you couldn’t tell apart. Has this happened to anyone else?.. I need some support I feel like giving up or completely going mia...