What Causes Stoppage In Periods With A History Of Pcos?

Dear Doctor, I have PCOS and I recently had an Hsg done 2 months ago. My tubes were reported clean.I have not had my period since. SInce then, I have taken 2 pregnancy test and they both said negative. I have had some symptoms of pregnancy. ex. nausea, but I'm not sure if I'm just stressed as well. What should I do?