Is this normal ?

I started taking seasonique (a combination pill) and my doctor told me that I should use back up methods for contraception for at least 7 days.

On the 8th day I had unprotected sex with my boyfriend and he finished in me. Is there a HIGH chance I could be pregnant? (Also, the pill i’m taking makes it so that I am period-free for 3 months at a time) I take my pill every day at the same time between 7 and 7:30pm never later than that. I’m having cramps, and normally (if i wasnt on the pill) I would get my period in about 4 days. Is this normal? In the back of my mind I’m thinking maybe it’s just my body adjusting to the birth control. (and yes i know there’s a small chance of pregnancy with any bc lol) is