What do i do about panic attacks?

Ok, my aunt was having a baby in lexington, and I live in ashland. I was in the back seat, my mom driving, and my grandma in the passenger seat. my brothers being in the middle seats (this is a van) and me in the very back. It was night and I was looking ahead in the road, and it ended in darkness because of the long stretch, and at this time my heart had started racing. I felt in total despair, panic, and like I was going to die. this was the first time this had happened. Now any time I think back to that, I get the nervous feeling that i did before i went into the small panic attack. I am planning on going to a protest in Columbus soon, and just thinking about this is making me nervous. what do i do?