Where did my sweet little girl go??

Anyone else's sweet little angel toddler become a raging whinny little demon after they got pregnant?? She is normal a very sweet good Lil kid but now she throws fits for no reason and just in general has become a monster! I put her down for her nap at 1145 which she normally goes down for no problem but today she just wants to bitch and cry rather than go to sleep and she is exhausted so she should have no problem going to sleep her diaper is clean she had plenty to eat and drink before nap so I don't know wth her problem is and right now is the worse time for her to pull this cause the fatigue migraine and nausea are ganging up on me and beating me down. Mommy just wants a nap baby girl please take yours so mommy can!!!