This combination of symptoms is rather vague, and a large number of different conditions ranging all the way from depression to mono and rarely to cancer can cause these symptoms. You can feel this way if your kidney, heart, thyroid, or liver are not working as well as they should or if you have some type of infection like HIV/AIDS. If you are losing weight and are feeling sluggish, your doctor can help you sort it out. Also talk to your doctor or pharmacist If you were started on a new medicine recently, as that may even be the cause.
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:
Depression is an illness that involves the body, mood, and thoughts and affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. The principal types of depression are major depression, dysthymia, and bipolar disease (also called manic-depressive disease).
Infectious mononucleosis is a virus infection in which there is an increase of white blood cells that are mononuclear (with a single nucleus) "Mono" and "kissing disease" are popular terms for this very common illness caused by the Epstein-Barr virus (EBV).
Drug interactions occur frequently. Get facts about the types of drug interactions, what substances or other things that may interact with drugs such as OTC drug and prescription drugs, vitamins, food(s) (grapefruit), and laboratory tests. Find out how to protect yourself from potential drug interactions.
Mumps is an acute viral illness caused by the mumps virus. Symptoms and signs of mumps include fever, headache, muscle aches, tiredness, and loss of appetite, followed by swelling of the salivary glands.
At MedicineNet, we believe it is important to take charge of your health through measures such as a living healthy lifestyle, practicing preventative medicine, following a nutrition plan, and getting regular exercise. Understanding your symptoms and signs and educating yourself about health conditions are also a part of living your healthiest life. The links above will provide you with more detailed information on these medical conditions to help you inform yourself about the causes and available treatments for these conditions.