You sound just like me right now. I have a 17 mo old (second baby). It took 4 mos for my period to return. Then I had my period, really heavy, for about 4 abnormally long and short cycles. Then nothing for 4 mos- not pregnant either. Went to the doctor and got some meds, which started my period cycle again. She also did an ultrasound and thyroid/hormone panel and everything was normal. But after three months of having my period again, I am now on another dry spell. It's been almost three months since my period. My husband has had a vasectomy, but the dr makes me take a pregnancy test. In fact, I need to pick up one on the way home today, take it, and then call the dr tomorrow. Wish I had some advice. Just know you are not alone. :(