Just off the pill, your periods can be erratic. Some women it takes a few months before they even have a period. I stopped bcps 2 months ago, and my first period was in 5 weeks, this cycle, I didn't ovulate until cycle day 21 (tracking basal body temperatures).
Also, stopping the pill can cause many symptoms similar to early pregnancy signs. For example, i've been nauseous since my last period, and i've had cramps, backache, and tender breasts all through this cycle but I know i'm not pregnant (have not had any accidents with our condoms, thankfully).