Pcos,periods and metformin????

Ok ladies I'm really hoping someone has some experience with this..

I'm on metformin in hopes to regulate my periods do to my pcos..Which was also very recently diagnosed..Any ways the first cycle on metformin came at cycle day 34 and it was heavy and painful the whole 5 days...And this there's my cycle now where I started spotting starting on cycle day 31..Which lasted 3 days or so then bam it's heavy..I'm on my 5th day and usually I would be ending by now but don't see that happening... Is this normal do to trying to regulate me??