AF started today...I think

Nina • 29, TTC baby #1, madly in love
I woke up overnight to go to the bathroom and  noticed I was bleeding.  I usually start midday, so a nighttime start was unusual and surprising.  AF was due on Sat., Feb. 16 according to Glow.  
This morning (luckily a snow day here on the east coast), I feel crampy and I'm cuddling my heating pad.  I suppose I'm out until the next fertile window.
​I'm now so confused about when my fertile window was.  Glow adjusted my period start date and my fertile window for January (made my most fertile day Jan. 29 instead of Feb. 1) when I edited what I'm assuming is the first day of AF -- today.
​Feeling sad, crampy and confused about how to plan for this month.