Sex pushed my period back

Leah
Ok so about two weeks ago i had sex with my bf! 
​We used protection (it didnt pop or anything cuz i took it off and threw it in the trash when we got done) 
​But THATS not the problem... I was supposed to start my period like two days ago and i Didnt!! prior i went to the docs and took a test (negitive... DUHHH cuz we used a condom) but usually when I have sex close to my period it pushes it back only like two days.. It's been like 5-6 
​Should I be worried????