Has this happened to you?

So my periods were never really normal, but I would get them every month or every other month just at different times and lengths. As I got older they seemed to come at the same time and I just started birth control about 4 months ago. This month (about a week or so ago), I had cramps for a day and then it seemed as if my period started but then the next day nothing. Here I am waiting for it to come. Has this happened to you before? Is this normal for it to like come for like a day then nothing?