Not Quite Sure How to Talk About My Adoption?

Hi everyone! :) I'm a 15 year old female and adopted from South Korea. I was adopted at 6 months old. I've recently discovered the reason for many of the problems that I seem to be having (one of which centers around my relationships with others.) I never knew that adoption could be why I'm so scared of being abandoned, and why I always think that everyone will eventually leave me. I'm not quite sure how to talk about this with my closest friend and my girlfriend. They've both experienced traumatizing things, including molestation, and they both feel as though they aren't good enough. My adoptive family is fantastic, I love them very much, but I can relate to what my friend says sometimes. Here a message she sent me that I could understand very well: It hurts me so much to think of a little girl who had all that matters to a young child taken away from them and learn so fast to face pain that she didn't understand and I've wrote and thought it about it time and time again but to realize that that little girl was me I don't know how to cope or accept it and no matter how I try to get over it what happened to me will always affect me and I'm so ********ing done with trying so hard to fix myself when someone else broke me before I had a chance to realize how much power they would forever have over me .. I hate acting like everything is okay and moving on is so easy and like I love myself and I'm done because that little girl still lives inside me and doesn't love herself or love her body lacks confidence and doesn't know how else she could get hurt but still fears it coming. I'm terrified that if I say I understand, she'll get angry with me because my home life has always been nice, and I've never been harmed beyond the loss of a birthmother. I don't know what to say to both my girlfriend and my best friend, because of the fear that they won't understand or they'll think that I'm just trying to make everyone feel bad for me.