I do think you have a serious case of whiplash. If you suffered seat belt bruises, you surely got whipped around. My daughter got hit in the right front fender by a car doing 40 and it gave her serious whiplash and a concussion. The first responders took her to the hospital because she was incoherent when they got her out of her vehicle. She never hit anything but the seat belt.

Seeking out a physiatrist (Physical Medicine and Rehabilitation) MD would be worthwhile.