R.D.
With my first and 3rd, I ended up starting my period while I was still breastfeeding (talk about HORMONES!)... with my second, I didn't have a REAL period until about a year after I had stopped nursing. The first time I got sick and I'm sure that contributed to an early menstral period, the 3rd time I know it was the stress of 2 kids and a newborn, which brought on a killer migraine, which triggered my cycle. My point is, it's different for everyone, everytime. I wouldn't worry too much about it, but if you're really concerned call your OBGYN and at least speak with a nurse... I don't think you really need to go in and get checked out quite yet. Best wishes!