You are not crazy at all. What you had what a reaction to a very real and recent threat. Trauma conditions us. Without realizing it a seemingly benign incident can trigger a whole range of emotions. You had a very normal reaction to a very real threat. PTSD can be brutal to deal with on our own. It becomes an issue in and of itself. To me it sounds like you are more concerned about your reaction than about being in danger right now.
I was sitting in pickup line without my phone when the bomb went off at the Boston marathon last year. I thought my brother was running and I know his finish tim.(he lives there and runs about 15 races a year, so I don't always know where he is running). I freaked. Completely lost it. I had to sit there for 25 minutes in line, 20 minutes from home, because i couldn't leave my daughter. My brother was ok. But I couldn't get over my overreaction to the event.
It wasn't until much later a therapist helped me realize that I was in the exact same situation when 9/11 happened. My husband works right there, I was trapped in a car with no phone and the announcer was screaming into the radio. It was like time stopped and everything went into slow motion.
I had no idea that that experience lodged in my brain. Hearing the radio announcer panicking over the Boston bombing brought an old experience front and center.
It doesn't always lessen the anxiety, but for me it helped to understand the magnitude of my reaction. My guess is that your reaction was as much if not more about the past as it was about the present. I hope that you have some counseling available to you, trauma can be difficult to deal with on your own. And I hope you take every precaution necessary to stay safe. Take care.