A hangover refers to a set of symptoms that occur as a consequence of excessive alcohol use.
Typical symptoms include fatigue, weakness, thirst, headache, muscle aches, nausea, stomach pain, vertigo, sensitivity to light and sound, anxiety, irritability, sweating, and increased blood pressure.
Alcohol is a diuretic, meaning it dehydrates you by increasing urine output. Drink water after each alcoholic beverage to prevent your blood alcohol level from rising too fast and to keep you hydrated.