Exercise affecting period

Guys I have a dilemma. I'm stressing out because I'm not getting my period it's approx  3 days late.  Im scared that I'm pregnant but I'm not sure because A month ago I started working out and eating clean so I'm not sure if that affects my period but also!! My boyfriend came inside me 4th day of my period & I was  highly stressed this month  So ... Can i be pregnant or is it due to the working out and stress? 
P.s my nipples are sore not my breasts