So here's the timeline:

I started my birth control pills between the 7th and the 8th (can't remember which day)

I ovulated the Friday the 17th

Had unprotected sex and he came in me 3 times Saturday the 18th

I'm now 9 days late for my period. Do you think it's my birth control making me miss my period, or do you think I could be pregnant?

I took two tests, one the day of my missed period and one the day after, and both were negative