I had a similar experience last night with ds - went to sleep as usual at 7.30, then started screaming at 9.30. He was sitting up in bed when I went in, but would not stop crying and screaming - wouldn't look at me or calm down when I cuddled him. I was thinking night terror, but after about 25 mins he finally calmed down enough to talk and he said "ear hurts". I asked which ear and he started rubbing his left one. He didn't want to lie back down, kept crying when I lay him down, so i gave him some panadol and let him fall asleep sitting on my lap on the couch. Put him back to bed and he was fine till woke at normal time this morning.

So, if he hadn't told me his ear hurt I would have guessed night terror. It's so hard to tell sometimes when they can't tell you what's wrong.