I want my Jewish last name!

I am the granddaughter of a Holocaust survivor. My grandfather’s family was separated and eventually killed during the Holocaust and he was taken to an orphanage run by nuns. He lived there for a few years before being adopted. When he did finally get adopted to a German Christian family they changed his last name to theirs. As a result, my dad inherited that last name, and so did I. It is a very popular not Jewish name. I have gotten really tired of having my Judaism questioned, and having people not from my religion ask if we are related. As a result I sometimes consider changing my name back to my grandfathers real last name to feel more connected to my Judaism. My family is proud of their new last name and claim that is who they are because of the people that adopted him, so it might be perceived as weird if I’m taking the Jewish family last name when they haven’t.

Thoughts?