Virginity

So Friday night I lost my virginity and I had sex Sunday and Monday and I was suppose to start my period Monday but now its Wednesday and I still haven't started! I am usually always on time and we didn't use protection he just pulled out and I trust that he didn't cum in me I'm just scared! And I havent told my gma that I'm sexually active and it will honestly kill her and I need some help!! Please someone help me!!!