My Last Is Period Is On 13 August 2016.normally I

My last is period is on 13 August 2016.normally I will get period for 25 days every month. Due to some functions I used primoult-n for 10 days from 6 the sep to 15 sep.yesterday (16 th September) it was bleeding and I think my periods started. But today I observed some thing in white like skin in my bleeding.can I know is this normal during periods.