"Diet" tips

When I say diet I'm not talking about weight watchers or anything. I just found out I have PCOS and I've been reading up for the dietary restrictions and there seems to be a very long list of foods I can never eat again. I was hoping to get some advice on how to make the change into the new lifestyle. Does anyone have any go to sites or books that helped them navigate? How do I know is the glycemic index is too high in a certain food? What were some tips or advice you were given in the beginning that helped you?