Help please...

...I’m only 16, 17 in December.Im only a junior in high school..I have a super regular period and it’s 3 days late...I’m absolutely terrified and have no idea what to do.My bf and his mother already know and are super supportive no matter the outcome...But I’m horrified to even take a test or talk to my parents.I already know they’d kick me out and disown me in a heartbeat...I have no idea what to do and I’m completely freaking out..If someone could please help me out and give me some advice that would be amazing I really need a big sister figure rn...