Am I️ pregnant

I️ am 4 days late for my period and it’s weird cause I️m getting all my period signs and I️ know it can be a sign of pregnancy too but I’m on birth control and my boyfriend wears a condom and pulls out so there’s a small chance that I️m pregnant. But I’m still worried. I️ think it’s just because my gyno switched me from 28 days on my birth control to 21 and I️ didn’t know I️ was suppose to skip 7 days after I️ take the 21 pills. Do you think that’s why my period is late?