How is one to feel, when having a head injury trauma in a car accident?

[CaliGurl]

I was t-boned by a Chevy truck in my Scion tc. As I looked over my shoulder, I lost focus of the car coming at me turning me into a 360 degree angle. As I proceeded to the opposite side of the road, I lost awareness of where I was, causing me to my head hit the windshield causing my back to whiplash. No broken bones, but a severe tense back. The Doctor said I experienced a mild concussion, but I have been feeling very off lately along with pain