I know I'm late to this thread, but for anyone reading this later as I was, I thought I should share. When I first started looking online for some answers it had been about 50 days from the start of my last period, and I was feeling some slight nausea and being emotionally sensitive (those were two things I had noticed when pregnant with my first child), so I thought I might be pregnant, but had already taken a few negative tests over the past couple of weeks. My husband and I had already been trying to conceive for over 6 months at that point. Now, it's been 80+ days since my last period, numerous doctor's appointments, and I just had an ultrasound that showed enlarged ovaries, cysts, and spontaneous ovarian hyperstimulation syndrome, whatever that is. So if you have this question, it may be worth a trip to the doctor to see if there is something else wrong. It's also worth noting here that before I had my daughter, my periods were always consistent, and I had no problems whatsoever. I have never been on any type of birth control or hormones or drugs. Best of luck to anyone else out there trying to find answers!