Late Period

So I have this app specifically so I can track my period to see how regular/irregular it is. It was regular, where I would start between the 12-14 of the month & it would last 3-5 days. I've been off BC for over 2 months now & my period is 20 days late. I have taken 2 pregnancy tests & they were negative. I don't feel any different... No mood swings, cravings, cramping, etc. Can this happen when you go off BC?