What are symptoms or dehydration?? are headaches and nausea symptoms?

Both can happen: Headache and nausea, sometimes experienced as dizziness, can happen with dehydration. Dizziness may be more pronounced when standing up. Other symptoms include dry or sticky mouth, thirst, and decreased or dark urine. It can be tricky to get rehydrated if you are nauseated. Try sipping on fluids rather than gulping. If your symptoms do not improve with hydration, notify your doctor.

Yes, see below: Dry, sticky mouth Sleepiness or tiredness — children are likely to be less active than usual Thirst Decreased urine output No wet diapers for three hours for infants Few or no tears when crying Dry skin Headache Constipation Dizziness or lightheadedness If the following occur, go to an emergency room: extreme thirst Low blood pressure Rapid heartbeat Little or no urination Shriveled and dry skin