literally SO confused!

hey everyone. I’m new here. so according to GLOW i ovulated on Dec 17th. AF is 8 days late which is super weird for me bc she’s like clock work every month (28 day length) i have mild cramping that’s been happening off and on since AF was due but still nothing. A few weeks ago my boobs were SUPER sore and as of today they feel really heavy and full with blue veins showing more than before. I got impatient this morning so i took a test and got a BFN. I’ve read that it’s best to wait 10 days after your missed period for a more accurate result but i know that everyone is different. —- so if i am, According to the calculator using the start date of my last menstrual cycle, i made 5 weeks today But I’m thinking that maybe my HCG levels aren’t high enough to detect.

ADVICE?!