Fast -
Mac and Chuck, as usual, are insightful. Trauma is cumulative and as one of the best books on trauma is entitled "The Body Keeps the Score" - Bessel van der Kolk. As you stated in you original post, you are still processing that terrible moment. I am so thankful for you and your children. At the same time, I am certain that every time you review that moment in your mind, you experience both an emotional and physical response. That's the trauma you still carry from that moment.
Here is a useful review of how one is affected: https://mytime.telemynd.com/telemyndblog/the-science-behind-ptsd-how-trauma-changes-the-brain-r16/?gad=1&gclid=CjwKCAjwx_eiBhBGEiwA15gLN2X2tU38E1eIg8NfvhAgpk0ujGuwAOQmEdl76brpYywoMKMRpcpB_BoCnasQAvD_BwE
Helpful options to get a handle on trauma:
If you do not know a therapist, talk with your PCP about this experience and ask for a referral to a mental health provider that they recommend
Check with your company's HR department - some companies offer Employee Assistance Programs which will provide, at no cost to you, a number of therapy sessions
http://www.ptsdalliance.org/help/ - lots of resources here
If you are a veteran: https://www.va.gov/health-care/health-needs-conditions/mental-health/ptsd/
Mental Health America provides a very useful online assessment tool: https://screening.mhanational.org/screening-tools/ptsd/
I am thankful that you and your children were safe from this experience physically. Emotionally, it won't hurt a thing to double-check your thoughts and feelings from that difficult day.