Periods

Hello, I am on mataformin tablets for my hormones. I have only been taking them for 5 days but I have come on my period. My egg hasn't released , because I haven't had pain in my left hand side of my vagina. But I'm not meant to come on for another 9 days. Does anyone think it's spotting or what's my problem? I don't have regur periods anyway but I'm always coming on late. Can anyone help me ?