I always thought that when it came down to TTC that I would just "know" haha I was so naive & with AF not giving me an exact  time frame every visit it makes it even more frustrating. Dh will not let me buy opks yet due to expense & he is stuck on "it will happen when the time is right" so there goes another thing making this increasingly frustrating for me.  Anywho I thought I ovulated around the 13th of this month, judging by CM and the use of these apps(I use 3different ones) the 13th&14th was the beginning of the window. On This past Sunday (day22 of my cycle) I went to wipe and I swore there was a light light brown tinge to it. A 2nd wipe verified it. I put on a liner and went to bed praying it wasn't AF getting ready to show. I woke up to nothing, went to work and another slight tinge of brown  possibly occurred and that was the end of it. I have had a few slight cramps nothing to write home about. And while I was at work I expierienced some nausea. I've read about implanation bleeding & feeling nausea  and cramps but with testing negative every time I take a pt in the past 6 months I fear it is just my imagination playing tricks on me. I am not due for any signs of AF for a while longer so I am not going to bother testing until I'm sure I'm late given her past of "28day", "35 days" games she likes to play on me...