Well, getting your tonsils out doesn't mean that you'd need to wean. Lots of moms have had some sort of surgery and have continued to nurse. But if you're ready for another kid and need to wean in order to get your fertility back, that's another matter. You might be able to coax your fertility to return by simply dropping some sessions. The longer you go without nursing, the lower your prolactin levels fall and the more likely it is that your estrogen levels will rise high enough to make you cycle. That's why a lot of moms get their fertility back around the time their babies start sleeping through the night.
IIRC, the average time until return of fertility for a breastfeeding mom is around 15.5 months. You're right there, really. I don't think you should consider yourself unduly "sensitive" to breastfeeding hormones until you've gone a few more months without a cycle.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"