I think that even with Doctor's theere is still much not understood about PCOS. The GP that diagnosed me, did so on my suggestion and I was the first he had diagnosed. He rang an expert in that area and sent my results over, also my symptoms who confirmed it for him. HE had no idea about how to treat, but researched it all for me and put me on metformin. A previous doctor had told me I was normal, even though the blood tests came back at menopausal female hormones and excessive testosterone, and other out of wack hormones, the androgen ones. Then the ultrasound confirmed it, as well as my symptoms. I didn't have the hair problem too bad, but had weight gain despite my heavy physical labour job, inability to lose weight, acne after not having it since my teens, weight gain, and complete loss of periods for many months.

I would personally get another opinion and definately get some bloods done. Take your U/S with you, or maybe ask for a referral to a specialist? Do you have the symptoms of PCOS besides possible fertility issues? Internal ultrasounds are supposed to be accurate, and many places don't even offer the external ones for pelvic examinations in my area (non pregnancy)