Teen pregnancy

So I’m 18, I’ll be a senior in high school starting in August, and I found out that I’m pregnant with my ex’s baby yesterday and I’m freaking out. My parents always told me at a young age if I ever got pregnant before I was married then they would kick me out. And I just want to say that I wasn’t trying to get pregnant, my ex told me that he was NO LONGER Fertile and that’s why we didn’t stay together he wanted kids but I told him that I was to young and that because he could he cheated on me with another girl that was pregnant with another guys baby. So I’m looking for some advice on how to tell him if I even should and how to tell my parents, thank you in advance.