It is unlikely that you have pre mature menopause and the symptoms you have described are due to immature Hypothalamic-ovarian axis.
Menstrual periods occur in the body due to cyclical changes in the hormones namely, estrogen and progesterone. The level of the hormones in the body is regulated but two very important endocrine organs called ovary and hypothalamus. It is only due to the proper synchronization of these organs that you will have menstrual cycles. These two organs are dormant in the girl's body till she reaches puberty. At puberty these organs start functioning, but as they have to still get in sync with each other, they are called immature. This immature ovarian-hypothalamic cycle leads to dysregulation of hormones and causes flushing, irregular bleeding and abdominal pain. They usually do not require any treatment and will mature by it.
Pre mature menopause, on the other hand, is the menopause before the age of 35 yrs. This, as you have rightly said is familial or due to radiation.
I would recommend the following-
1) If you are worried about premature ovarian failure, I would recommend you get a serum fsh level checked. They would be abnormally raised in this situation.
2) Take Tab. Mefanimic acid or tab. Tylenol 500 mg to reduce the abdominal cramps.
3) Eat a good balanced diet with good portion of proteins carbohydrates and vitamins. Consume diet rich in green leafy vegetables and milk.
4) If the symptoms get too distressing, consult a gynecologist and discuss the use of oral contraceptive. They help in regularization of the cycles and prevent the symptoms.