I know women I work with had been feeling their menstrual symptoms two weeks before actually starting their flow. I seemed to pick up on others symptoms also the week before starting my own. It was a great learning for me realising what is mine and what I am picking up from others.
This can be part of balancing although uncomfortable. Red raspberry root amongst many other herbs are helpful in transition. Several years a go I had a dream that my cycle would begin to link up with energies beyond the moon and that I would have more insight to in a sense evolve the flow in ways that seem more balanced. I was discouraged by much external opinion on women's menstruation and chose a diff path with more balanced spin. Odd thing perhaps but I was prompted to give a sort of gift of menstrual blood back to the earth at times and in so doing began to notice an increased co nnect ion to nature. One may also choose different ways to give daughters insight into this transition. I found this one a bit ago. My daughter participated and learned although told me it was 'weird' haha. http://www.womanwisdom.com/w_coa-menarchekit.shtml
I have also found this essential oil blend to be very helpful.