What Could Cause The Following Symptoms: Slight Dizziness Followed By

What could cause the following symptoms: slight dizziness followed by 2 to 3 three seconds of an extreme unpleasant spinning sensation immediately followed by violent nausea and vomiting and sweating followed by chills. I have had this about 4 times over the last two years. I have never had prior to the last two years. An hour after the episode I feel normal again.