Signs of mild or moderate dehydration include:
Thirst
Dry or sticky mouth
Not peeing very much
Dark yellow pee
Dry, cool skin
Headache
Muscle cramps
Signs of severe dehydration include:
Not peeing or having very dark yellow pee
Very dry skin
Feeling dizzy
Rapid heartbeat
Rapid breathing
Sunken eyes
Sleepiness, lack of energy, confusion or irritability
Fainting
Shaking not a symptom