Warning signs of dehydration include weakness, low blood pressure, dizziness, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, confusion, or urine that's dark in color.