So the headaches got pretty bad last night, and are still somewhat worse today (and in the new spot after the rear-ending). I'm hoping it's just from the adrenaline and stress of a panic attack (I couldn't feel my arms an legs afterwards I was so worked up). I came home to get quiet rest, but it seems I've only felt worse since I've gotten here from head jolts.

I don't think my head moved 4 inches, as I was well braced with both arms on the steering wheel and back arched. Maybe 1-2 inches. Does this significantly change the G forces involved (I'm a biologist, not a physicist!)?