Hi, I had gone through your question and understand your concerns. I dont think that something is wrong. Chances of pregnancy are minor, but plan b may cause certain hormonal abnormalities and it may last for several weeks. ALso, intercourse may cause some painful uterus contractions and delayed period if plan b is taken after it. YOu need to take nonsteroid painkillers at this point and wait and see if symptoms will worsen. If do, you should do ovarian ultrasound and check hormonal levels including pregnancy test. Hope this answers your question. If you have additional questions or follow up questions then please do not hesitate in writing to us. I will be happy to answer your questions. Wishing you good health.