not gaining weight

weight loss

decreased sexual desire in males, difficulty speaking, poor appetite, weight loss

Clinical depression (also called major depressive disorder, or sometimes unipolar when compared with bipolar disorder) is a state of intense sadness, melancholia or despair that has advanced to the point of being disruptive to an individual's social functioning and/or activities of daily living. Although a low mood or state of dejection that does not affect functioning is often colloquially referred to as depression, clinical depression is a clinical diagnosis and may be different from the everyday meaning of "being depressed." Many people identify the feeling of being depressed as "feeling sad for no reason", or "having no motivation to do anything." One suffering from depression may feel tired, sad, irritable, lazy, unmotivated, and apathetic. Clinical depression is generally acknowledged to be more serious than normal depressed feelings. It often leads to constant negative thinking and sometimes substance abuse. ... 

left upper quadrant abdominal pain, stomach pain, upper abdominal pain, vomiting

Gastroenteritis involves diarrhoea or vomiting, with noninflammatory infection of the upper small bowel, or inflammatory infection of the colon, both part of the gastrointestinal tract. ... 

dizziness, passing out, vomiting, weakness

Dehydration (hypohydration) is the removal of water (hydro in ancient Greek) from an object. Medically, condition in which the body contains an insufficient volume of water for normal functioning. ... 

cough, pain in several joints, poor appetite, weight loss

Human immunodeficiency virus (HIV) is a retrovirus that causes acquired immunodeficiency syndrome (AIDS), a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections. Previous names for the virus include human T-lymphotropic virus-III (HTLV-III), lymphadenopathy-associated virus (LAV), and AIDS-associated retrovirus (ARV). ... 

increased sweating, muscle weakness in foot (feet), palpitations, weight loss

Hyperthyroidism (or "overactive thyroid gland") is the clinical syndrome caused by an excess of circulating free thyroxine (T4) or free triiodothyronine (T3), or both. ... 

increased thirst, not gaining weight, urinating often, weight loss

Type 1 diabetes (formerly known as "childhood," "juvenile," or "insulin-dependent" diabetes) is actually not mostly a childhood problem. The adult incidence of Type 1 is similar to that for children, which is one of the reasons the preferred term. Many adults diagnosed with Type 1 have been misdiagnosed as Type 2, which has been partly accountable for the misconception of Type 1 as a disease of children. ... 

nausea, stomach pain, upper abdominal pain, vomiting

A peptic ulcer is an ulcer of one of those areas of the gastrointestinal tract that are usually acidic. A more general term, peptic ulcer disease (PUD), is also in use. Most ulcers are associated with Helicobacter pylori, a spiral-shaped bacterium that lives in the acidic environment of the stomach. Ulcers can also be caused or worsened by drugs such as Aspirin and other NSAIDs. Contrary to general belief, more peptic ulcers arise in the duodenum (first part of the small intestine, just after the stomach) than in the stomach. About 4% of stomach ulcers are caused by a malignant tumor, so multiple biopsies are needed to make sure. Duodenal ulcers are generally benign. ... 

irregular menstrual periods, poor appetite, stomach pain, upper abdominal pain

Alcoholism is the consumption of or preoccupation with alcoholic beverages to the extent that this behavior interferes with the alcoholic's normal personal, family, social, or work life. Alcohol consumption caused by alcoholism can result in psychological and physiological conditions, and ultimately in death. Alcoholism is one of the world's most costly drug use problems; with the exception of nicotine addiction, alcoholism is more costly to most countries than all other drug use problems combined. ... 

decreased sexual desire in males, difficulty sleeping, poor appetite, weakness

In everyday language depression refers to any downturn in mood, which may be relatively transitory and perhaps due to something trivial. This is differentiated from Clinical depression which is marked by symptoms that last two weeks or more and are so severe that they interfere with daily living. ...