Assuming that you meet the criteria for villagers breeding, check under your village. Make sure there aren't villagers stuck in a cave somewhere nearby.
Also, check for other villages that might be spawning and/or breeding. I'm pretty sure there is a maximum number of villagers that you can have for the whole map.
Put a fence or wall around all the village or breeder, so that the villagers can't escape, then break all the doors. Then, just put them back, and maybe add a few more.
Also, check for other villages that might be spawning and/or breeding. I'm pretty sure there is a maximum number of villagers that you can have for the whole map.