Beginning 4 month of metformin

I'm on my way to the 4th month using metformin. September was pretty normal as far as periods go. October and November have been weird. I missed my period for October and I've been spotting pretty much all of November.

For pretty much the whole year I've been having problems with my period. I've only had about 4 periods this year. I was just wondering if anyone out there has experienced this as well? Or something similar. Does it take a while for metformin to balance out hormones? Or should I consider secondary options?