Pregnance possibility with new birth control user

Patient: Hello, I had a question about birth control.I recently started taking birth control and I’ve been on it for about a week now. I started it on the first Sunday following my most recent period and I had heard that it was more effective to start it then, than starting it in the middle of my cycle. However, I had unprotected sex on Saturday night and he came inside me. Is there a possibility that I may get pregnant even if I continued to take my birth control in the past 2 days or should I be okay?