Hello and welcome to HCM, Tiredness can be due to a number of causes however, one of common causes of tiredness includes anemia or low hemoglobin levels. Thus, I suggest you to consult your primary healthcare provider for clinical assessment and complete hemogram. Complete hemogram will determine hemoglobin level and peripheral blood examination will determine the type and probable cause of anemia. In case anemia is present, it has to be corrected with appropriate treatment. High temperature i.e. fever can occur in number of conditions. Accompanied nausea suggests some problem in the gastrointestinal tract (GIT). Thus, clinical assessment of the GIT is required to determine the cause of these symptoms. In the meanwhile symptomatic treatment can be started in the form of anti-pyretic or drug for fever. Thanks and take care Dr Shailja Puri