Stopping birth control and no period

So I’ve been on the pill for about 1.5 years. The week of Christmas was my week of placebo pills and I got my period. I didn’t continue birth control after that. My period for this month was due on the 24th and I still haven’t gotten it or any signs of it such as cramps like I normally do. Is it normal for periods not to be regular after stopping the pill? Or should it have gone back to a regular schedule right away? Before the pill my periods were pretty regular.