Morning after pill (ECP)

So I took the ECP (emergency contraception pill) on Tuesday and it is currently Sunday, my period was due on Wednesday but it is late and for me my period is never late. I know the pills side affects mean your period can be late but I was just thinking it may be by a day or so. But I didn't get any other side affects after taking the pill so I'm not sure what to be thinking. Can someone please help me out with some reassurance that this is normal