TTC post pill

Tahlia • 👼🏻👼🏻🤰🏻🌈
This is the first time in my life that I have been off the pill (first af experience was when I was 12 and I'm now 22). I have been taking the pill pretty much ever since I started menstruating as I have HORRIBLE pains 😷. I stopped taking the pill after my last period 12/12/16 and I gathered that I have a 28 day cycle (I wouldn't know) so af should arrive today but hasn't shown her ugly face. I took some tests, all bfn
My question is - when should my period come ? And when will they start becoming regular ? 
Thank you