Pregnancy

Okay so I've only had sex 3times all safe with a condom on, but my period is late.
​I mean I show no signs of any change in my body so I'm really confused and scared.
​I've been reading that stress can cause it to be delayed and I'm already  highly irregular as it is (like extremely) 
​So maybe when I'm worried of not getting it it's actually causing me to not get ??
​I don't know, I'm just really scared right now.