Me and my girlfriend had sex about a month ago, the day that she got off her period. When we had finished we looked down to find that the condom had come off of me and was sticking to her leg. We weren't sure if the sperm had landed in the condom before being pulled off or if the condom had come off earlier during sex and I just had not noticed. To be safe, we went to the pharmacy and took Next Choice. Soon after, I want to say four days, my girlfriend had a bloody discharge, but we were unsure if it was a period. She is late for her period now by a week. Her friend told us that when she took Next Choice, she missed her next cycle completely and restarted the following month. Is that normal or should we be worried?