These symptoms will most commonly be related to dehyrdration. If you are recovering from a viral stomach illness or you have been exercising in the heat, then try to start with rest and hydration. If your symptoms do not improve, then please contact your doctor.
While the list below can be considered as a guide to educate yourself about these conditions, this is not a substitute for a diagnosis from a health care provider. There are many other medical conditions that also can be associated with your symptoms and signs. Here are a number of those from MedicineNet:
Dehydration is the excessive loss of body water. There are a number of causes of dehydration including heat exposure, prolonged vigorous exercise, and some diseases of the gastrointestinal tract. Symptoms of dehydration include headache, lightheadedness, constipation, and bad breath. Treatment for dehydration is to replace lost fluids and electrolytes.
Hereditary hemochromatosis (iron overload) is an inherited disorder in which there is excessive accumulation of iron in the body. Individuals may have no symptoms or signs, or they can have severe symptoms and signs of iron overload. The most effective treatment for hemochromatosis is therapeutic phlebotomy.
Type 2 Diabetes
Type 2 diabetes is a chronic condition that may be reversible with diet and lifestyle changes. Symptoms include excessive thirst, frequent urination, weight loss, fatigue, and an unusual odor to your urine. Most people don't know they have type 2 diabetes until they have a routine blood test. Treatment options include medications, a type 2 diabetes diet, and other lifestyle changes.
Type 1 Diabetes
Type 1 diabetes mellitus (juvenile) is an auto-immune disease with no known cause at this time, although there are a few risk factors. Symptoms of type 1 diabetes include frequent urination, unintentional weight loss, dry and itchy skin, vision problems, wounds that heal slowly, and excessive thirst. Type 1 diabetes is diagnosed with blood tests. A healthy lifestyle and controlling blood glucose levels can improve life expectancy.