i had night terrors from puberty until i was in my early 20s. i found that they ocurred much more frequently when i was dehydrated and when i was exhausted and over tired and when i was menstruating or ovulating. of course an emotional upset lurking in the back of the mind doesn't help. i used to try to wake myself up by scractching on my pillow. i saw a documentary about kids with night terrors and they say if they happen daily that they usually will happen in a particular part of the sleep cycle and that if you can predict at what time, you can wake the child five minutes before its going to happen and then they'll fall back asleep and have missed the episode. however if its only for 3 days it might be something else bothering him. i've also heard that kids have bad dreams when they are going through developmental advances, like they may be remembering running or jumping, or maybe he's even remembering someone pushing him at school or something? my 3 yr old also recently does a lot of moaning/whining in his sleep and i've heard there is something about this age, but i don't know why. i know how scary and upsetting it is and i hope it passes quickly! kids don't usually remember bad dreams at this age, if that's any comfort.