Hi I Took Postinor 2 March Last Year 2015 And

Hi i took postinor 2 march last year 2015 and since then my period came just for two month but drop little and since then i did not experience my period again till now i did pregnacy test serverally but still prove negative and of a recent i did a pregnacy test but still negative and my breast became swollen and bigger of a recent ,my issue what can i take to restore my period? pls am really border and scared. Thnks.