Thanks for your reply. I did have an ultrasound, she said that everything looked normal aside from my uterus being larger than normal, which she attributed to my having 3 pregnancies. PCOS was never brought up as a possibility. I'm guessing that the ultrasound didn't point in that direction.
You definately need to get a diagnosis. No period, with no explanation, for 2 years should have prompted your doctor to look for things such as PCOS, and this is commonly linked to weight gain and body hair. (Not necessarily though, my mother had it badly and was always very skinny and not hairy!)
Have you had any ultrasounds?