I also vote for motion sickness. I was feeling like my head was spinning and I was dizzy feeling. It was only when I was a bit weak and tired. Somebody on this forum mentioned that it might be due to neck muscle weakness. I started paying attention and I realized that the reason that I feel like my head is spinning is because it really is all wobbly. I had not noticed. If you can feel like your head is spinning from weak neck muscles, you can also have motion sickness.