Confused 🤔

Michelle
I am officially over a week late for my period but every pregnancy test I've taken says negative! I've taken 3! The last one I took was on Sunday.  I started mildly working out within the last 2 months...but haven't lost a significant amount of weight.  I've heard that a new workout plan could affect your period but never heard of it making you miss your period all together. Looking for advice...any and all advice is appreciated! 
P.S. My boyfriend and I BD around ovulation time....so that's why I'm confused!Â