Please don’t judge, I need help

Hi, so I’m 17 and I’m really scared and confused. I fucked up and had unprotected sex, more than once and now my period is 6 days late. I took one pregnancy test a couple days ago and it was negative, but I still haven’t gotten my period. I don’t know how to tell my mom that I think I might be pregnant. She’s very strict and I know she’s gonna freak out no matter what, but what’s the best way to tell her?

And before anyone attacks me in the comments, I know it was stupid to have unprotected sex and we shouldn’t have done it but we can’t go back in time to change it so now we have to deal with the consequences.

UPDATE: I started my period and nearly cried tears of joy 😭 I DEFINITELY learned my lesson and won’t be having unprotected sex until I’m ready to have a child 😂 thank you to the supportive comments, they were very helpful 💞