I would not be so quick to say you are not hurt!
I was rear ended by a Honda Pilot I was sitting still in my 98 RAM like yours and she was doing 30. I had a severe whiplash and to this day m neck is still not good at all.
Her airbag did not go off and the shoulder harness broke her sternum.
She hit me dead on the rear bumper and the only damage to my truck was that hitch, bumper and the frame where the hitch attaches. I absorbed the impact! No crumple zine is not a good thing. Her brand new Pilot was totaled.
A lot of times injuries don't instantly show up. I would suggest you go see a Orthopedic to make sure you are ok!