I don't think what you're going through is unusual. When TTC our first I went off the pill in April 2005. I charted BBT to track fertility. I ovulated once at the end of July (no pregnancy, 130+day cycle) and once on Sept 9 (conceived my son!). He's now 15 months old and we'd like to TTC again, but I still haven't gotten my period back from having him.
Right now, and while TTC my son I took Vitex (chasteberry) and drank lots of green tea. The Vitex has good clinical studies behind it and is a natural cycle regulator - you might consider that. Although since it's herbal it won't have nearly the strong and direct effect of hormones. The green tea is good for you anyway, and I've noticed it makes my cervical mucus more fertile (TMI maybe, but hey...).
I always assumed my kids would be 2 years apart too, but with no period in sight I figure it's just Mother Nature's way of telling me to wait a few more months. I think any time between 2 and 3 years apart is good spacing and your kids will be good friends. I'm sure things will come around for you eventually. If you're slim/borderline underweight, try putting on a couple pounds (this is harder than it sounds!) If you exercise a lot, make sure you're eating well. If you're still breastfeeding (I still nurse my son 2x/day) this can also affect your fertility, though lots of moms I know have still managed to get pregnant. If you haven't picked up a copy fo Taking Charge of Your Fertility by Toni Weschler, I highly suggest you do. You'll learn a lot about your body and the TTC process is much less frustrating. Anyway, good luck!