Does anyone have any information about stress and menstruation or experience w/over exercising causing loss of periods?

I am 32 and have been off my progestin only birth control since June 2008. Since that time I have had maybe 3 periods. But, I have also lost some weight (I was not overweight, but I am not underweight now) and over exercised for about4 months. I also quit my job, interviewed for a bunch, and then finally moved cross country for a job. Once I got here, I had another job offer, and was stressed out for about 1 more month over whether or not to take that new job. Then, once I decided, was stressed for the last month over whether I chose the right one.

I have calmed some, but have not had a real period since Oct 2008. I really want to get pregnant, but obviously cannot right now.

I have been to a reproductive endocrinologist. There is a possibility I have PCOS (but I don't have insulin resistance, nor hair growth/balding, nor weight gain). I am on estrogen now to see if we can kick-start my pituitary.

I am under strict orders not to stress out, but it is difficult to focus on not being stressed, when all of this is stressing me out.

Can anyone out there relate to heavy stress and ammenorhea?

Thanks!