Hey! The Period Tracker should show up once your Sim experiences their first period. I will most likely be changing that behavior a little because it seems that a lot of users are confused about it.
As for the pregnancy thing, I cannot confirm your issue in my game, so there's unfortunately nothing I can do about it right now. I would like to know why you're having these issues though, so if you learn anything, please let me know. Perhaps you have another mod that affects things?