Hello, and I hope I can help you today. First of all, I want to clarify, if you are virgin and have not had sexual intercourse or ejaculation directly in the opening of your vagina, your chance of pregnancy is really nonexistent. Sperm die when exposed to air, so there is no way that you can become pregnant from sperm that ejaculated outside the vagina. Furthermore, is very uncommon to find women who ovulate during their menstrual cycle. Therefore, you were most likely not at the fertile time of your cycle when you and your boyfriend had genital contact. Furthermore, irregular bleeding can be caused by travel, changes in weight, hormonal imbalances and stress, especially the stress of worrying about getting pregnant. Just because your period was light this month does not mean that there was anything wrong. No women s menstrual cycle is exactly the same every month, and as long as you got a period at the usual time, there is no reason to suspect pregnancy if the bleeding was different in quality than what you usually see. So I think that it is fine to be reassured that you did not conceive from this encounter with your boyfriend. If you continue to have irregular menstrual cycles for more than three months, you may want to visit your local physician as some hormonal imbalances can cause these problems and should be tested for. I hope that I was able to adequately answer your question today, and that this information was reassuring. Best wishes, Dr. Brown