It does sound like a night terror. DS had them from when he was about 1 to 5 or so. They eventually became less and less frequent, and shorter as well. Nothing would rouse him properly and he would just cry 'mum, mum!' even though I was right there. It does seem like the more you try to console them, the worse they get. A few times we managed to completely wake him up and then he could get back to a normal sleep, but it was rare (he has always been hard to wake), and I am not sure it is recommended either. Hopefully for you it is just from the loss of routine and he won't have them again.