Bulky Ovary and CA125

Hi, sorry for the long post and not sure I should be on here as I am driving myself crazy, I'm 37 and on 13TH September I had an ultrasound due to my horrendous periods, I lose blood clots the size of the palm of my hand, this has been going on a long time I'm constantly anaemic and I have had scans in the past and all they have shown is a small fibroid. Lately I have been having bad lower back pain that radiates into my pelvic area and hips. I honestly just put it down to old age. 
May bowels aren't great but I put that down to ibs. 
 

anyway I had my scan and just over a week later the GP rang to say I had polycystic ovaries, New To me, I'm only a slim girl, I'm not hairy but I do have some symptoms. I accepted it was that and she said I needed a hormone test. 
I had the hormone test last Monday and I didn't hear anything so I thought it must be fine. I was referred to gynae back in august and I still haven't heard anything.

Tuesday I rang my GP for some cream and whilst on the phone she said I'm really sorry but the other Dr requested a CA125 an ovarian cancer test and it's been missed I'm so sorry, well this is new to me?  She said the nurse will ring you. (She did and I had the test yesterday afternoon) she also requested a stool sample? 
I asked the receptionist for a copy of my scan report today and it actually says I have an enlarged bulky ovary 13cc with multiple follicles could possibly be PCO. 
As you can understand I'm really worried now? I never thought of a the Big C. 
 

could a bulky ovary indicate cancer? Has anyone had experience with this?