Would love some thoughts on the situation.

I have been off of the pill and TTC since around September. For my first three periods they were super regular, and I could pinpoint when I was ovulating due to symptoms. Well since November it has been all out of wack... So I bought some OPKS and started using them after my last period which was January 27th. I still have yet to get a positive. But around the 13th-14th it started to get darker but then it lightened up and is now barely there. And now since the 18th I have had headaches every day, one of them being a migraine. I've taken 3 PTS and BFN. I'm so confused. Any insight or thoughts on this would be much appreciated.

Sorry for the long post....