Nausea, severe headache, loss of appetite & balance, fatigue, tingling, muscle weakness(legs), vomiting, severe lower back pain.negative head ct, mri.guesses?

Numerous symptoms: This is certainly a severe condition, and you must continue to search for a cause. Get several specialists involved. This may be a severe reaction to some unexpected toxin. Look carefully at the history. Did ths start after a specific even like a vaccination e.g. Gardasil or vaccine booster? Gardasil is given to girls about 15 reactions tend to be under reported. Keep searching for the cause.