The causes of dizziness, nausea and fatigue have many aspects, as follows: First, carbon monoxide poisoning: mainly in the bath, if the gas leakage in the house, or gas burning is not sufficient, it may lead to carbon monoxide poisoning with the above symptoms. Second, cerebrovascular disease: for example, cerebral infarction, can appear dizziness, nausea, fatigue. Third, food poisoning: if you eat unclean diet, especially seafood or expired food, it may lead to the above symptoms. Fourth, hypotensive shock: dizziness, nausea and weakness can also occur. In short, there are many aspects of the causes of these symptoms, and you need to go to the hospital for a clear diagnosis.