I'm on birth control(alysena) and I Got my period on April 4 It ended the 8th In the next week I got the birth control I'm on the 28 day pack 2nd pack didn't get my period when I was done the first pack I even waited a day or two without taking them and it still didnt show up I started taking the again and now I'm like 10 days in on my 2 ND pack and I still haven't got it what could it be??