Sometimes I am serene, my patience almost endless...sometimes I am a horrid beast, and just for a snap second I don't know myself. I have said terrible things and thought terrible thoughts. And it's weeks (months even) of sleep deprivation that brings me to my knees.
But I have to grant myself (and you too) this - despite my little lapses I'm still here and I'm still parenting in a way I'm happy with.

Partly, maybe, it's about altering your expectations for yourself - you're a human, you're not perfect, and yet you're doing a fabulous job. Imagine how wonderful you'd be if you got plenty of sleep!

And I've thought about the conflict of needs thing too. Maybe it's more of a perception of conflict than an actual one. DS needs me in the night; and yes I need to sleep, but I also need to care for him and know that he is happy. So perhaps I need to find another way meet my need for sleep - get someone else to help, for eg - rather than accepting that there must be a conflict.