All the signs that you do not drink enough water

Thirst
Dry mouth
Fatigue
Sadness and irritability
Dark yellow urine
Decrease in frequency of urination (6 to 7 times a day is normal)
Dry skin
Dizziness
Bad breath
Headache
Muscle cramps
Signs of severe dehydration
The following symptoms indicate severe dehydration:

Excessive thirst
High heart rate
Loss of consciousness
Accelerated recess
Empty gaze
Low blood pressure
Extremely dry skin
Important Dizziness
Absence of sweat even in hot weather
Very dark urine, little urination