I think it depends on how you do it. I would be fairly low key about it so as not to worry them. I tell DD1 that mummy is tired because DD2 doesn't sleep well and when I get tired, I can get grumpy so I need her to do what she's asked without fuss ie. getting dressed, putting toys away, that sort of thing.

If I can, I try to do this after she's had her bedtime story - I find because that time is distraction-free she's much more likely to absorb the msg. Oh, or in the car when she can't run off!

Good luck and hugs - it sounds like you're having a really rough time Onyx.