~ Food Has Power ~
I never get night sweats, but instead breast tenderness during the same this following article says most women get them (about 1 to 2 weeks before onset of menses, then it stops promptly the hour menses start.
Hopefully someone in the Heal Thyself group can offer personal experience and a remedy, but this is all I've got.
Maybe this could help : http://en.wikipedia.org/wiki/Hot_flash
It says : Younger women who are menstruating or expecting to menstruate soon (the premenstrual period typically lasts one week) may encounter hot and/or cold flashes. These episodes do not usually last long, with feelings of cold and heat alternating over the course of as short as a minute. Hot and cold flashes for younger women tend to occur only during times of menstruation or pre-menstruation (when estrogen is typically lowest). If they occur at other times in a young woman's menstrual cycle, then it might be a symptom of a problem with her pituitary gland; seeing a doctor is highly recommended. In younger women who are surgically menopausal, hot flashes are generally more intense than in older women, and they may last until natural age at menopause.
Another article :