How do I get over my fear of going off the road again?

I know there are answers that tell you how to deal with accidents, but my case is different. On sunday my brother was driving my moms car, my grandfather was sitting up front. I was behind my grandfather, meaning I had the right view. I told my brother he was too close to the wall and he didn't listen to me, he moved over again and his right front wheel hit the rock and he lost control, sending the car totally over. I'm a firefighter so instinct said get everyone out, and I did. On to the real question, after the crash I didn't have a problem, but today when someone was driving, and come close to the right curb I freak out. Now I know that "time will make it better" but I'm really afraid were gonna crash again. As if theyll go on the curb and crash too. To me it's embarring for me to say because everyone was going, "Ohh your a hero", "Your a great firefighter" and "You weren't scared when everyone else was." Truth be told I wasn't but now I am, so someone please, tell me how to overcome my new fear. Thanks in advance