2 weeks late?

my boyfriend & I had sex on July 5th & he finished inside me. my last period day was June 29th but I don't know when I started ovulating...
​I took a pregnancy test July 20th but it was negative. i was supposed to get me period July 29th but i'm now 2 weeks late. 
​I was in a car crash August 1st & was very stressed out that day, but i'm not stressed now. could that be why my period is late? or should I take another test?