Hi, Thanks for posting in HCM. Sprintec is combination hormone medication of progestin and estrogenis, which is used to prevent pregnancy. It works mainly by preventing the ovulation during your menstrual cycle. It also makes vaginal fluid thicker to help prevent sperm from fertilization and changes the lining of the uterus to prevent attachment of a fertilized egg. Hence, when you were already on birth control ill, it was not necessary for you to take Plan B. Plan B One-Step is a type of emergency contraception. It contains levonorgestrel. It prevents pregnancy by preventing or delaying ovulation or by interfering with fertilization of an ovum. Since you have taken both, there will be delay in periods as it could be expected. Anyway, you need to get your periods within 3 weeks from the day you have taken Plan B. Otherwise, you need to seek medical attention immediately. Hope the information provided would be useful for you. All the best.