Since being on Metformin, my cycle has been 41 days for a good few months now, BUT, on days 37, 38, 39, and 40 I get "spotting", not enough to need a sanitary towel or panty liner, it's just a bit there when I wipe.
I never have had spotting before, and since the Metformin it's always 4 days of light spots, then AF starts in full proper force.
It's also confusing me , in that is the first day I spot the first day of my cycle, or is the first day of full flood AF my first cycle day? 
Have been told I'm not eligible for IVF, as DH has a daughter, even though she is now 26, so how that affects me I don't know! I could understand if he had loads of little kiddies with various women, but one dauughter, so old that I have never had the chance to be in her "growing up" life, as I only met her when she was 21!!
Not sure if we could get IUI, I'm going to ask.
Help, this babymaking is making me crazy!