Spotting with metformin

Emma
Has anyone had any spotting after taking metformin for a while?
​I've taken it for 31 days & yesterday I had a small amount of pink in my CM & 3 tiny clots but absolutely nothing for the rest of the day & nothing today either.
​I haven't had AF since Jan 5th 2014 & never had spotting in my life before.
​Any help would be greatly appreciated please, thanks