Help! When does AF come for you?

Lorraine
So I have PCOS and my cycles are very irregular.  I got my first very positive OPK on 4/6/16.  I've been checking HPTs daily, all negative, but still no sign of AF showing up.  How many DPO are you when AF shows up?  I'm 15 DPO now and thought I would either have AF or a BFP by now.