What could nausea, tunnel vision, and fainting be signs of. had an ekg, eeg, blood tests, tilt table, echo, neurologist and cardiologist visits.?

Vasovagal: Did you have a positive tilt table ? This can be vasovagal. It depends on your medications, work up.

Hyperventilation?: Often the simplest explanations need to be considered. Dr. Azimi was also very wise to consider vasovagal reactions. In lieu of an ekg, a holter monitor might reveal a rhythm disturbance when you are not in the office and experience these problems.

Maybe panic attack: It seems that you have gone through quite a bit of ordeal, and i assume the results of those tests are all normal? If so, the symptoms you have maybe from panic attack which is quite common and very treatable. If your symptoms occur more often during period of rests or in some specific environment such as super market etc...Panic attack is more likely. Please follow-up with doc. Good luck.