i had protected sex on the april and it was my first time, and my periods should fall on 4th of may but that month my periods came on 28th April and remain for 2 days only, then i did UPT it was negative, i was ready for my periods to fall on 28th of may but i can not see my periods coming till today, I had done UPT on 29th may too and it was negative, today is 31st may and I can't see my periods