My boyfriend and I were having sex last Sunday, and when he pulled out, the condom had slipped off. He never ejaculates inside me, and this time was no exception, but I took the Plan B pill about 36 hours later, just to be safe. My period has never been extremely regular or predictable. Until January or so, it wasn't uncommon for me to go 3-4 months between periods, but for the past few months, it has been becoming more and more regular. If it were 100% regular, I would have started Tuesday, but I didn't, and I don't feel any symptoms of an imminent period. I know that there is a possibility that I could be pregnant, but is it more likely to be a combination of the stress of worrying about it, irregular cycles, and the Plan B pill?