Found adult daughter I didn't know was mine

She contacted me. Wanted a paternity test, I ordered one and had it mailed to the both of us. I am her father but I knew I was when I saw the photos of her. She told me she just wanted medical history and didn't want a relationship. I feel pretty devastated I had held out hope that I could get to know her. I feel like have been cheated out of something in life, I know I have a good life but this is just really hard. I hope she has a change of heart and is just trying to process all of this. I have always felt like something was missing from my life, I blamed a lot of the feelings on my parents neglect but now think this could have been why even though it may sound silly. I don’t know why it is so hard for me to get over this, you would think I have no bond to this person and being a guy it would roll off of me but I can’t shake the way I feel it’s such a horrible sadness.