Period three days late

Okay so I was supposed to start my period the 18th and still no AF. I recently just came off the depo (4 years on it) and when they took me off they started me on the pill so my body wouldn't be shocked I guess. This month is my first month "natural" (without birth control). Do you think it's normal for my period to be this late or could it mean I'm pregnant? My period on the pill was really light and lasted like a week. Aslo we have been using condoms and withdraw during sex but neither are 100%