Sudden onset of motion sickness, vertigo, dizziness, nausea. Any ideas as to what is wrong with me?

For about 3 weeks now I have been having unexplained motion sickness, dizziness, vertigo and nausea. It is worst when I'm in the car. For some reason it seems worse in the late afternoon and evening hours. I have not yet vomited because of the dizzy spells, but I have had dry heaves a few times the past few... show more For about 3 weeks now I have been having unexplained motion sickness, dizziness, vertigo and nausea. It is worst when I'm in the car. For some reason it seems worse in the late afternoon and evening hours. I have not yet vomited because of the dizzy spells, but I have had dry heaves a few times the past few days. The spells also come when I am working on the computer or even just moving around. Anyone have any ideas as to what is wrong with me? At first I thought it was just a sinus infection that affected my inner ear, but it seems to be getting worse over time and my cold is gone. Even sitting and writing this, I feel like the world is spinning.
If it helps, I have never had this motion sickness before. Crazy amusement park rides and boats are some of my favorite things in life. Well, they were until this anyway. =(
Any help would be greatly appreciated, I'm kind of at my wit's end.

P.S. Please do not tell me to see a doctor! I have an appointment, but not til February.
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