Plan B

Ladies..you know sometimes you have to take a morning after pill... let’s talk about side effects. I got my period again after 3 days after taking the pill ( I had a period a week before that). Since I didn’t take Plan B for a looong loooong time I don’t remember if it’s normal or not. And my stomach hurts so much like a have a real period. Is it ok? Anyone knows and how long should I expected it?