Before I read your final message, I was going to blame it on teething. My daughters used to do the same thing. Still do. Whenever there is a sleep disruption or have a hard time going to sleep at bed time- there is normally something up. Either they are teething or getting sick. Just keep that in mind whenever it happens. It's so hard and frustrating at the time, but it's only for a while. They'll be back to normal again.