I was wondering what are the stages of dehydration?

See below: No definite divisions, many causes, vomiting diarrhoe, sweating , commonly mild dehydration, can be countered by oral rehydration if possible, does not cause much disturbance in blood pressure, pulse is higher, and you feel thirsty severe dehydration , where blood pressure is low, sometimes very low, a shock like state, may require intravenous fluids for correction.