What Causes Neck And Middle Back Cracking Sound, Headache, Vomiting And Dizziness?

I fell late last night. I tripped on my son's toy and landed against the wall. I heard what I can only describe a nausaus crack in my neck and middle back. I have had a severe headache and vomitting. I was diagnosed with GBS 4 yrs ago. I am dizzy and can't remember things that happened minutes before or hours before. I don't know what to do and I am scared.