Enlarged Ovary/Ovulation Pain

Hello --

I am 35 years old.  In 1994, my left ovary was removed due to a very large dermoid tumor and also a fluid-filled cyst.  Since then, I had two children and my cycles were usually 32 days or so and pretty regular.  Since I weaned my daughter in early 2001, I have had varying amounts of pain at ovulation on my right side.  I know this can be normal and my doctor found nothing on an ultrasound done about two years ago.  I suspect that my hormonal levels have fluctuated in this time period -- I have experienced, at different times, more hair growth in unwanted places, more breakouts, energy fluctuations.  I was diagnosed with anemia about two years ago, which was resolved with supplements, but I think I am probably anemic, or borderline, again.  Over the last year, the pain has changed from a very specific pain to more of a radiating pain in the same area.  I also have mild cramps at ovulation, and sometimes I have backaches either from my period to ovulation or from ovulation to my period.  An ultrasound a few weeks ago found that my ovary is now "enlarged and at the upper limit of normal", according to my doctor's office.  The nurse told me the doctor says the ovary is just working overtime since I only have one.  I question this, since it apparently didn't have to work "overtime" for the first seven or eight years.  Is this likely?  I know an enlarged ovary can be a sign of ovarian cancer, as well as other things, and I'd like a little more reassurance, I guess. My symptoms are usually not debilitating, but they are worrisome to me.  

Thank you very much.