Doctor said I have pcos

Well I went to a gyno yesterday because I had a period going on 13 days did lots of labs every thing came back normal so yesterday he did a scan and i found out that I have lots of cyst forming a chain on my ovaries he said that it's pcos and it explains why not getting pregnant after trying for almost two years . What I don't understand is October when I did my scan they never seen that only one or two but now it's on both and they are forming a chain now I have to try loose the weight to get pregnant