HI,
I think its the Provera, not the metformin. I also take provera to get a period and i take metformin.
I have only been taking 500mg of metformin (scared to increase) :-)
I noticed that with the provera, I had a heavy bleed, next month it was just light, then the next month it was medium.
I don't think there is anything you need to worry about, as long as you are getting the period then its all good!
i spotted on saturday and sunday and monday was light now this morning nothing....? maybe it will pick up this afternoon. i'm confused!
Did your period just start? Sometimes you can get spotting for a day or a few days before full flow starts. My RE has me count the first day of full flow as CD1.