PCOS and no periods...

Im 30yrs old, recently married and worried I might not be able to conceive. I have been diagnosed with PCOS. I don't get a period... well I do but its very few and far in between. over the last 3yrs I have a total of 3 periods. 2 of them being in the last 3mnths. I have missed this month's which tells me that my body has gone back to not having periods. I am worried that this will effect my chance of having kids. I have been told its all about my weight and that PI women (I am half fijian) suffer this due to weight but what I can't understand is why, when at my heaviest, did I get two periods regularly and why has its stopped. Has anyone been through the same problem? any suggestions or advice?