Plan B side effects and periods

Patient: My girlfriend took the plan b contraceptive on Tuesday and had Stomach pains for the few days after. On the following Monday she started bleeding which is only a week after her previous period started. And now A week after (following Tuesday) she has been experiencig vomiting. Are these common side effect or does she need to seek medical attention?

Doctor: Plan b can lead to irregular periods. However the fact that she is vomitting also concerns me about a possible pregnan ncy and I would advice her to take a home pregnancy test just in case. Please consult a doctor in person. All the best.