Symptoms of menopause in 20s?

Ive had a total hysterectomy. Im only in my twenties and im getting terrible symptoms of the menopause. Im on hrt and ive even tried changing to a different drug and that didnt work. I get severe hot flushes, terrible moods, headaches and feel really tense. My GP is useless and now im facing more surgery as well - Does anyone know of anything that will help? Please!!!!