What are the chances of becoming pregnant?

I’ve been taking a birth control for almost 2 months called microgestin fe 1 20. I am a Sunday starter as well as a period day 1 starter. My boyfriend and I started having sex about a month and a half in. I took a pregnancy test and I’m fine but I recently had sex on the brown pill (sugar pill) I am paranoid i’m pregnant because I’m on the 3rd sugar pill and nothing yet.. my friends say i’m not and so does my health teacher.. what do you think?