BIG (((((((((((((((((((((((((((HUG))))))))))))))))))))))))))))))))) Gwenavr!
I had similar symptoms about ten years ago and had extensive testing done finally to find I had a herniated disk in my neck caused by a car accident a couple years before that went undiagnosed. ( It was also missed in my first MRI) It was positional meaning if I moved a certain way the nerves would be cut off causing the vision and dizziness trouble thus the nausea...
I went through extensive physical therapy and have been great ever since...although now I know I can "fix" it myself when my symptoms begin to appear...so far no surgery has been required! You may want to see if our lovely Gem has any suggestions to at least make you feel better for now...Try a post in the Reiki or Crystal healing forums too
Sending some positive energy your way!!!!