Metformin and pcos

I started metformin a little over 2 weeks ago. I have pcos but my periods come every month but they are really heavy. I’m not ovulating like I’m supposed to. I have been feeling sick like throwing up for like 5 days mostly after I eat or at night time. My period is supposed to start today, but 2 days ago I went to the bathroom and there was pink blood when I wiped so I thought I started my period early. But nothing has been on a pad since or when I wipe. Is metformin making my period weird or could I be pregnant?