Oh, *flyingsolo” of course your feelings are valid. What you feel is what you feel.
Maybe what you long for is something different though. That sense of belonging, in your case to a family.
I was brought up in a big family, some of us adopted, some of us birth. Some of us loved the big family and have remained close all our lives, some of us needed more me space and have kept minimal contact as adults. Everybody is different in the closeness they need,
I think you have a picture in your mind of what it could have looked liked for you. But maybe, even if you had been brought up with them, it might not have been like that picture. I know one of my brothers always felt that he was on the outside looking in.
I had four grannies and grandads because of my adoption. My bond with each one of them was different, because we were all different people.