Heat exhaustion and heatstroke are two potentially serious conditions that can occur if you get too hot.
More information on Heat Exhaustion is available here.
Carbon monoxide is a poisonous gas that has no smell or taste.
More information on Carbon Monoxide Poisoning is available here.
Hypoglycaemia, or a "hypo", is an abnormally low level of glucose in your blood (less than four millimoles per litre).
More information on Hypoglycaemic Disorder is available here.
Important: If you have these symptoms, they may be unrelated to any of these conditions listed. If you are concerned about your symptoms then you should see a doctor.