Tried a 7pm BT last night, at it was the same story. I just completely abandoned doing WI/WO because I literally could not handle 1.5 - 2hrs of it again, so I just stayed with him right from the get-go and it look him 45mins - 1hr to drop off. It was the same at nap time today and I had to stay with him for him to fall asleep.
I am really starting to wonder if it's not simply a matter of routine, but some kind of development leap or separation anxiety (in combination with the teeth). We've never had BT issues before even if he was a little OT or UT so I can't understand why his behaviour would all of a sudden swing sooo far from normal. He's also been just plain angry. He had 1 NW last night and the only way I can describe it was pure rage...hitting me, trying to bite my hands, just complete hysterical shrieking and nothing was calming him down. It took me and hour to settle him and then DH ended up having to sleep on his floor from 3am - 5am.