Pregnant

Please can someone help me out. I don’t know if I’m being paranoid or what but my period is late by 8 days and I had sex with my now ex bf last Saturday and he put it in and I took it out straight away because he didn’t have a condom on but I’m just confused as to why I’m late. I’m only 14 so it might just be irregularities but some advice or signs to look for would be great thanks x