I have whiplash, how do I treat it?

I wrecked my truck Wednesday morning. I totaled my truck. The tree won. I lost control after having a dizzy spell and passed out. I was very fortunate. My guardian Angel was quite clearly with me. The main injury is whiplash. I am in quite a bit of pain. How do I treat this medically? Would physical therapy help or should I try something else. Thanks for your input.