What Causes Irregular Menstrual Periods While On Dronis Pills?

hi, i am 27 and had severe cystic acne during my early twenties,when i consulted a dermatologist i was suggested to use dronis20 as my testosterone levels were high. i ve been using them for 3 years now..i tried to stop using them several times but when ever i stoptaking the pills i experience severe hairfall and my skin looks awful..and i would start using them again..but from couple of months i am having early and irregular periods..and very soon we are planning for a baby..just wondering what is causing my early periods and how can i stop using these pills without any sideeffects. your reply is very much appreciated.