I'm freaking out !! pregnant?

I'm pretty sure I'm pregnant. I'm  on the smaller side and I'm only 19 I feel like I'm to young ... or if able to without my body failing on me . I just need some one to tell me it's okay . My parents will be disappointed so will my Fiancé's ... I'm so scared i can't be a mom I'd be terrified. How am I supposed to raise a kid if I was never raise right. Guys I'm so scared I want to cry. I have a whole life to live I can't have a kid I'm not ready .