Pregnant at 16?

I had sex a week ago. I’m on the pill but my period is late. That has NEVER happened before and I’m really worried. I’ve heard that you can get pregnant even though you’re on the pill, but I’m only 16 and don’t know what to do next. Should I wait and see? I feel like I can’t talk to the guy I had sex with, and can’t buy a pregnancy test since I live in a VERY small village and know the people who work there very well. I can’t talk about it with my parents either cause the same thing happened to my sister (she had a miscarriage at 16) and they only got mad. Any tips on what I should do?