I'm not Murph, but I went through a period of time (close to a year) where I was having cycles of 16 days 3 times in a row, then 2 normal, then they would be 16 days long again. During that time I also felt tremondous PMS systems (very sore breasts, terribly out of sorts), when normally I had very little. I was exercising regularly, taking soy protein, vitamins. I went to my doctor and he ran all kinds of test to make sure it was hormonal. (Endometrial biopsy, blood work, etc.) He had me take progestin for 3 mons. to see if that got my cycles back on track. I continued having the same problems. So now I take progestin for 10 days of my cycle, starting on day 15 and that has solved the problem. 1 or 2 times a year I will still fall short of a normal cycle, and recently I have skipped a period, but it has made such a difference, for me. I hate having to take the pills, and have considered changing to the natural progesterone cream. I agree that Christine Nothrup book will help explain what your body is going through. Take care