What Causes Dizziness, Weakness And Rashes On Legs, Arms, Chest And Abdomen?

I am 49, in good health, not overweight. Five days ago I felt extremely fatigued with some dizziness with raised temperature. Some mild muscle and abdominal pain but no nausea, loss of appetite or diarrhoea. This morning (still tired and weak) I now have rash on legs arms back chest and abdomen (not face) not itchy or hot. What could this be?