Why do white people scare me sometimes?

I am a black girl i live in a predominantly black neighborhood. But when i go into more diverse neighborhoods with white people i tend to get very afraid. I don't understand why, but there bright skin scares me, and it makes me very nervous even though i try not to show it. Is this normal? Does that mean that i'm racist? I do have a mild anxiety disorder but when i'm around them it heightens, i don't know why i get so scared. I don't think i'm racist but i don't think that this is normal. Any suggestions?