I have very long breastfeeding amenorrhea, also. With my first, I was pumping a ton of extra milk while working, and I got my period back when I equalized my supply to my 1-yo's demand. But with my 2nd and 3rd, I didn't get my period back until 6 weeks after weaning completely. With my 3rd, I was down to 1 feeding per day for a month or so, and I still didn't get my period back until 6 weeks after giving up the last feeding.
Anyway, you are totally normal, and many women would love to have an easy way to space out their kids naturally. But if you want to get your period back, there are things you can do to encourage it.
http://kellymom.com/ages/older-infant/fertility/ This is a pretty good article on how you might encourage your period to come back without weaning entirely. But like I said, with my second two, there was nothing I could do to get my period back until I weaned completely.
Good luck,
Jenna