Your description is consistent with a moderate dehydration
problem. The reasons for dehydration are many.
First of all I suggest you to take natural electrolytes like Coconut water, barley water
, lemon water with salt etc to releive from the symptoms of dehydration.
It also makes sense to meet a doctor if you have recurrent problem to know the reason for it. The mild to moderate dehydration can be managed at home, severe cases need admission in the hospital.