I’m so scared and need advice

I’m fifiteen. me and my boyfriend tried new condoms... they didn’t look like the right fit and I told him they looked to big. He assured me they were fine. Well it slipped off inside me during sex and he came inside me and we didn’t know until he pulled out.... I had a panic attack and freaked out so we went to the store and bought a plan b and took it, but then I look on here and it said I’m ovulating. Is the pill still gonna work. I’m so scared and crying because I’m not ready for a baby and my parents don’t want me to use birth control because they don’t think I have sex so birth control is not an option in the future because they will murder me.... someone help me calm down or what I should do.