When To Expect The Next Periods?

Hey. I look levonelle on the 26th of March, two days after failure of a condom during intercourse. My last normal period started on the 11th March. After this, I had symptoms similar to gastroenteritis for two days. A light period occurred approximately a week after taking the medication and was shorter than normal/approximately one week early. When should my period be expected; the week early lighter one, or the approximate date that I m used to? It s been a month since taking the medication and I am yet to have a proper period and am obviously worried! Thanks.