Morning after pill

I had the morning after pill around 3 days after my last period! About 1 week later I experienced a spell of about 2-3 days of bleeding, a normal flow and I was told this is normal after researching! Now, 2 weeks later when my official period is due in around 8 days I am feeling slightly crampy and have quite sore breasts, which is normal for me around my period! Does this mean I will have another period?! Help? Should I worry