Advice/Thoughts?

I went off of my oral birth control pill in July of this last year (2015). July, August, September, October and November I had 28 days cycles. December was a 30 day cycle.  I have been diligently tracking my ovulation and should have ovulated according to OPK cycle day 14 this month. AF was due yesterday 01/21 according to glow which would have been my 28th day. Yesterday, I had intense cramping that lasted for a period of a couple hours. The cramping went away, later yesterday evening I noticed a very very small amount of brown tinged cm. Still today no signs of AF. And no cramping. Took a pregnancy test last night and then again this morning which have all been negative. Advice and thoughts please!