Pregnancy scare and delayed periods

Okay so I'm 16 and I just started being sexually active and had sex for the first time on 28th of March and had sex 3 times since then the last time being 18th April and my period was supposed to start that day. We used protection every time and he pulled out too .

It's been 11 days and i haven't had my periods, could it be because of a pregnancy scare or stress and my messed up sleep schedule or am I pregnant? I also have irregular periods ever since i first had them.