Siobhan,

I understand your sleep deprivation.  My daughter Abby is now 10 years old and sleeps great.  However that was not the case the first four years of her life.  She was three before she slept through the night for the first time.  It got better as she got older, until she finally stopped getting up at night.  She also had night terrors and would wake up screaming, or would scream in her sleep.  The doctors told me to not let her sleep for long periods, waking her up before getting to that stage of sleep.  I had a hard time doing that.  I hated waking her up because she had a hard time going back to sleep.  The night terrors got better with age as well.  They got fewer and longer time between.  She still has bad dreams, but nothing like the night terrors.  The only thing that I can say is hang in there and try to rest when your son is resting.  I know how hard that is at times because you have a hundred things to try to get done while they are resting, but you need your rest too. 

Good luck,
Greta Holmes
Kentucky, USA