Glad everybody is safe although shaken up. I used tho think whiplash was just a scam for people to try to get money from insurance companies until a hit and run driver hit me twice on the interstate about a decade ago and pushed me into the concrete lane barrier.
Just like you I had turned in my seat to see where the truck was at that had already hit me once when he hit me again hard and into the concrete. It twisted my neck and back. It took months for my back to get ok and even longer for my neck despite physical therapy.
Just make sure you do everything the physical therapist tells you to do!!
Your accident made me think of a co-worker who came back from lunch one day shaken up because he happened upon an intersection right after a cement mixer truck had tried to take a turn at too high a speed and rolled over on top of a small pickup waiting at the stoplight. The truck and the man in it was just a few inches high.