How do I not stare when I see a dark skinned black man?

Years ago I was brutally d by a tall dark skinned black in an alleyway which obviously left me traumatised and to make matters worse he almost beat me to death when I threatened to call the cops. Now when I see a dark skinned black man its like my gut drops in fear and I shake. Sorry if this is offensives but they literally frighten me especially when i'm in public. I can't go near them without panicking. I know this may have been a bit rude but its getting worse and I want to overcome this problem.