I’m confused

Donella

My period is a week and a half late. It’s never been this late. I honestly think it may be too early to tell but I’ve taken two pregnancy test out of just being anxious but both they came back negative. My husband and I had a two week span of sex because he’s stationed overseas (from the 1st-15th) so I know it could be possible but if it’s not then why is my period so late. Any suggestions??