I'm glad that you are choosing now to deal with this issue and I applaud you.
I speak better German than I speak my own language. I feel like a fraud for trying to speak my own language and my own language is not English. In my country there are two official languages - mine is not one of those.
My people were mistreated by the government, subjugated, terrorized and all but essentially stamped out. I grew up wanting to be a good Canadian. To this day I do not share my First Nation's heritage voluntarily with people for fear of retribution. I do not know the traditional ways of my people and when I try to learn, I feel guilt, shame and embarrassment. To feel this way is not right, but I can't help it, I am a product of centuries of oppression of my culture and heritage; oppression that is still visibly ongoing to this day.
I know exactly how you feel. I've hidden my background all of my life and each time I admitted it, if I didn't directly lose an opportunity, I lived in fear of losing opportunities. I still do and I've walked this earth for over 40 years. It is an injustice to have the ability to take pride in your own background stripped forcibly from you, that is why at times in my life, I wish I could stand proud in defiance of those who would further contribute to the oppression - but I still can't.
You feel alone without an identity to fall back on. You feel like a single blade of grass trying to push back a hurricane. I had often thought of trying to re-connect to my heritage in the hopes that it would help me heal from PTSD but I have been "colonized" and so am now an oddity unto my own people. It is very difficult hating what you've become, wanting to go back to your roots but finding those who practice your own culture now reject you.
My advice to you is to grieve it out, work through it. It is going to be painful but if it sets your soul free, then the pain is worth the limited time it will exist. You have a culture, you have a heritage, you are not a demon or undeserving of the pride in that identity. You cannot paint an entire people on the example of just one person, that person is not representative of your heritage or your culture, they do not speak for you, only you can speak for you.
Do small things, just like in PTSD recovery, baby steps will get you far. I began painting in my traditional forms. I began to learn my language. I learned my history (here be wise minded - know that historical accounts come from eyes that are one-sided, you need to be open minded about all that you read and understand that prejudice can hide itself as education as well). You need to talk through the pain, resolve it and find the things that place the meaning and pride of your heritage back into your heart.
You find what you need from it and you carry that with you into your future with pride.
I wish you luck on your journey. ((Hugs))