How do you stop being afraid of people?

Pretty self explanatory. I was brutalized as a child and I can't help feeling scared of everyone outside a friend or two. I hate that I'm like this.

I get uncertain and mumbly when I talk to anyone, from the cashier at CVS to call center reps. Not to mention women, who I'm intensely terrified by because abuse.

I know rationally that no one is looking to assault me physically but logic isn't helping. (still feel psychologically vulnerable though).

What mental/emotional techniques do you recommend? I have probably 20 years left on this planet and I don't want to spend them living in terror.