I Was Diagnosed With Pcos In Late 2015 And Started

I was diagnosed with pcos in late 2015 and started taking medication. Six months later I came in for an ultra sound and the doctor told me that all the cysts were gone and I could take my medication for about one month then quit it. Ever since I stopped my period got out of balance again and I haven't had my period for almost 3 months and I've never been so confused because from what I read I understood that pcos had no cure and many women who are affected by it undergo diets and other methods in order to avoid it's negative effects. So how come I stopped my medication and how come my doctor never told me about these methods. Im honestly really frustrated and I don't know what to do im only 17 and parents do not have any knowledge about this disease and my doctor refuses to share hers with me.