Irregular periods but TTC!

I got off of BC Nov.30th of last year. I got my AF dec. 2, then dec.24 and the last time I got my AF was jan.29th. That currently puts me at 40 days since my last period. I took a test last night but got a BFN. Right up until i got my  last period (Jan. 29th) I swore I was pregnant because I had all the symptoms- nausea, dizzy, sense of smell was heightened, extremes breast tenderness, craving bugs etc but then AF came. Now I don't even know when I am ovulating so that we can actually know when to try. Did anyone go nth rough this or something similar?