What Causes Irregularities In Menstruation?

hi my period is not coming since 3 month and iam 26 .and iam consul the doctor she giving me provera and birth controll and my mistake iam taking both all day .but my period is not coming.doc said stop the pills and 10 days wait i hope menses is coming.tell me what can i do,can i consul again and againg starting provera