help! metformin issues!!!

So I'm on cycle day 55 since my last period. I started metformin a few months back to help me get my BFP. I've only had 1 period since July when I started metformin. This cycle I had my period for 16 days with light spotting throughout and am waiting to get my period. I usually start around day 40 but nothing and am getting all BFN so I know I'm not pregnant. I'm not sure if my cycle is sooo long because of the metformin or what but I'm going insane!!!!! Anyone have the same issues on metformin? I'm on 1000mg/day and am taking prenatal vitamins and B12 tablets.