Whats going on??

I typically get my period around either the end/beginning of the month. But here I am. 2 weeks later. Still no period. No symptoms of a period nothing. At first I thought I was just starting to sync with my roommate but she's on her so I should have mine by now. Right? I do have a boyfriend and every time he cums it's typically in me. Today I took a pregnancy test and it came up negative. I'm highly confused.