How do you get over anxiety of driving?

So anxiety disorder runs in my dad’s side of the family. My dad doesn’t have it, or at least not as bad. But me, my grandma, and my aunt have it. My aunt doesn’t drive at all. And my grandma use to drive, but as she got older, she stopped driving all together.
I’m terrified to get into a wreck. Fender benders, are not as bad for me, but they still shake me up quite a bit. I KNOW if I ever get into a wreck, i’m not ever driving again, granted, there are times I drive to places I shouldn’t go like a guys place who isn’t the best choice for me. But we all make those mistakes.
And we need driving to get to other places too, like the grocery store and work. So I NEED to drive, but I know I won’t, if I get into an accident. And i’m 25, it already stresses me out knowing I have more decades of this. I also get VERY tense when driving AND being in a car. Even when my own family drives, and there all good drivers, and I never use to be that way when they drove.
There was one time my friend was driving me, and another friend, and my friend t-boned another car going straight across 4 lanes of traffic, I was in the back seat. I couldn’t stop shaking till it was over, and it litterally took me a year in a half till I could drive with out being as scared again. I just can’t handle another one at all, and I know I won’t ever drive again, if another one happens. I always get less tense, when ever i’m out of a car, and litterally feel like going to rest, or sit in a hot tub, or work out to calm my nurves. I don’t even like long distances, driving on high ways, or driving in the city. I always love when I get out of a car, and get to relax in my bed for the night. NO ONE can live like that, and live knowing they have decades of this.
Please tell me what I should do about this.
Medication doesn’t help.